The rational optimist guide to using AI
"Show us how to use this thing!"
When I asked if you wanted to learn about artificial intelligence (AI), you practically broke my inbox. The message was clear: "Show us how to use this thing!"
We've seen amazing advances lately, from SpaceX landing rockets like darts to Boom Aerospace bringing supersonic jets back. AI is different. It's not locked away in some research lab. It's available on your laptop right now, ready to help you work smarter, think better, and create more.
This isn’t a 10,000-word manual covering every possible way to use AI. That would be like writing a guide to the web in 1995—obsolete before the ink dries. AI is evolving so quickly that today's uses might look quaint compared to what's coming next month.
Instead, I’ll tell you how I’ve used AI to get a lot more done in a lot less time.
Nine months ago, I was exactly where you might be now. AI was more frustrating than helpful. Then I tried the latest versions. Now I can't imagine working without it.
This is one of many diaries where we will explore how to use this incredible new technology. No technical background required. Just curiosity and a willingness to try something new.
Imagine having a brilliant personal assistant who never sleeps, crunches complex data in seconds, and creates custom lessons for your kids. That’s just a taste of what AI can do for you today.
There are many “AIs,” each with their own strengths. I few months ago, Claude was my chatbot of choice. Now I prefer OpenAI o3 and Google’s Gemini 2.5. I use them at least 50 times a day. The monthly subscriptions are the best money I spend.
Pro tip: skip the free versions. For around $20 a month you can access premium AI models that are dramatically more capable.
Don't start by asking "How do I use AI?" Instead, think about what you want to achieve.
Learning Spanish? AI is your patient tutor, available 24/7 for conversation practice.
Building a business plan? It's like having a Harvard MBA on speed dial. Need to teach your kid geometry? It'll create custom practice problems that adjust to their level, complete with step-by-step explanations.
You'll find your own way to use these tools. I'm here to show you what's possible, and I can't wait to hear how you end up using it.
Forget needing 10,000 hours to master a skill. You can get surprisingly good at AI in about 10 hours.
It's 7 am. My desk is buried under hundreds of pages of notes about AI, robotics, and breakthrough tech. I love this stuff. I’d happily spend weeks diving deep into these innovation rabbit holes. But there's a problem.
All these fascinating notes need to become something useful for you, our readers. And that's when the fear hits. The blank page stares back and my brain is frozen, wondering how to connect these ideas.
This was my every-morning battle. Then I hired the perfect writing partner: AI.
I dump all my research into OpenAI o3 or Gemini 2.5. My “prompt” is simple: "Using these notes, write an essay on [topic]."
It spits out a terrible first draft in seconds. Yes, terrible. But it conquers the blank page and gets my creative juices flowing. It's like having a brainstorming buddy who's always ready to riff on ideas.
I end up throwing away 99% of what AI writes. What matters is AI gets you unstuck and shows you angles you might have missed entirely.
AI then becomes my ruthless editor. Need simpler language? More concrete examples? All you have to do is ask. Get creative: "Explain this like Warren Buffett would."
AI’s real superpower is speed and instant feedback. Instead of wrestling with a stubborn paragraph for an hour, I can ask for 10 different ways to explain the same idea in minutes. The
couldn’t exist without AI.Pro tip: Give AI context. The more background you provide, the better your results. Treat AI like a new team member. The more it knows, the more helpful it’ll be.
Getting up to speed on a new topic used to mean days of reading, hoping you didn't miss something crucial. Those days are over.
Before digging into a topic, I’ll ask AI to serve up the 10 most important articles ever written on it. No more wandering through Google hoping to strike gold.
AI is a shockingly good research filter. Instead of drowning in dense academic papers, I have OpenAI o3 or Gemini 2.5 analyze them and pull out the key insights. The trick is being specific: "I'm trying to understand why supersonic jets couldn’t make money. What are the three strongest arguments in these papers?" Without clear direction, AI misses the mark.
Want to fast-track your learning? Try AI role play. "You're an experienced quantum computing researcher. You've just hired a junior researcher. What are the five most important things they need to understand about this subject and why?"
My friend and economist
gave me a simple but powerful tip: Ask AI more questions. Treat AI like your intellectual sparring partner. It’s not Google. Don't just ask for facts. The best insights often come from the back-and-forth.I was recently reading about Lockheed Martin's Skunkworks in
’s excellent new book Boom. I wondered about similar rapid innovation projects. One quick question to AI, and suddenly I had fascinating parallels from history. Before, this would have been days of research.This is a revolution in reading. Every book is now a conversation. I bet within two years, you'll be able to highlight any passage on your Kindle and get AI commentary instantly.
AI isn’t perfect, but it does 80% of the research grunt work in 1% of the time. You now have a team of tireless research assistants at your fingertips. Learn to use them.
Two simple AI tricks that save me hours each week
Taming YouTube. Found an interesting hour-long talk but don't have the time to watch it? I generate the video's transcript, feed it to AI, and ask it to pull out the five key points. No more skipping valuable content because I'm short on time.
Transcribing data. I needed data from some graphs in the book "100 to 1 in the Stock Market." Instead of spending hours squinting and typing numbers, I asked AI to convert the image into usable data. What used to be mind-numbing transcription work now takes seconds.
This is just scratching the surface of how AI fits into my daily routine. Think of it as an incredibly versatile assistant that can guide you through almost anything.
Need market updates? ChatGPT's new "Tasks" feature will check the S&P 500 chart each morning and give you the highlights.
Ask yourself: What routine work makes you less valuable? What tasks serve no real purpose and numb your brain? That's your AI opportunity list right there.
The goal isn't to replace thinking, it's to give you more time for it. Let AI handle the grunt work so you can focus on what we humans do best: spotting unexpected patterns, developing fresh insights, and solving thorny problems in creative ways.
"Dad, how do airplanes fly?" You know that moment when your child asks a fascinating question, and you fumble through an explanation.
That's where my journey with AI at home began. It's transformed how I teach my six-year-old daughter.
Instead of muttering something vague, I turned to Claude and asked it to create an interactive game showing how airplanes fly. Within seconds, it spat out a simple but engaging simulation. Soon we were playing with a model where my daughter would change wing angles and air speed, watching in real time as her "airplane" soared or dipped.
AI transforms how kids learn. As Rational Optimist parents (and grandparents), it’s our duty to know this stuff.
Remember in The Matrix where Neo instantly "downloads" kung fu into his brain? That's basically possible with coding now.
When Apple debuted the App Store, it sparked a gold rush and created billion-dollar companies like Instagram and Uber, along with tens of thousands of high-paying coding jobs. But there was always a velvet rope: You needed to speak the language of computers, aka code. Not anymore.
Now you can create software by simply describing what you want in plain English. It's like having a world-class programmer on speed dial, ready to turn your ideas into reality.
Yes, AI is already world-class at coding. OpenAI's latest model ranks among the top 125 programmers globally. The founder of AI coding assistant Devon (a multiple-time world coding champion himself) says AI will be the world's best programmer within two years.
It’s telling that when Italy temporarily banned ChatGPT, coder productivity there dropped by 50%.
In my day job as Chief Investment Analyst, my firm recently analyzed every US stock from the last 20 years to uncover what the best performers had in common.
My partner
spearheaded the project. Here’s Dan:Pre-AI, this would have required data scientists, a six-figure budget, and probably a year.
Instead, it took 2 months and two $20/month AI subscriptions. Using mostly Claude, I wrote code and automated data acquisition from several different sources to ensure integrity. Then using mostly ChatGPT, I parsed the data to tease out the golden insights.
The craziest part: I had never written a single line of code in my life before this project.
We're entering an era where the question isn't "Can you code?" but "What do you want to build?" The next Uber or Instagram could come from a teacher with a vision to fix education, or a teenager with a wild idea and a laptop.
Why not you, Rational Optimist?
Try it. Think of a simple task you'd like to automate, maybe analyzing your monthly expenses. Describe it to AI in plain English and watch your idea come to life.
A fun example of what's now possible for us coding mortals:
I've been tracking my sleep, recovery, and strain (via Whoop) for about six months. I copied my personal data into an Excel file, uploaded it to Claude, and asked it to find patterns for improving my health.
In minutes, it created a detailed analysis with all kinds of insights like “don’t work out within two hours of bed” and “eat dinner earlier.” I even had it code a dashboard measuring my sleep patterns since our third child was born on November 22.
You can see my new son George had sunk me deep into “sleep debt!”
Remember those $500 Rosetta Stone programs we bought to learn new languages? Those days are over.
I know multiple people using AI to learn Spanish, Hebrew, and other languages. AI builds you a personalized course, complete with exercises and role-playing scenarios. It grades your work, corrects your pronunciation, and adapts to your learning style. Why would anyone buy a textbook or sit through a lecture again?
AI also gives you an expert doctor in your pocket.
Take Susan Sheridan's story from The New York Times. Her face was drooping on one side, she couldn't speak clearly. The ER doctor sent her home, calling it "benign." Susan typed "Facial droop, facial pain and dental work" into ChatGPT.
The AI's response was clear: These symptoms matched Bell's palsy and she needed urgent treatment. Susan rushed back to ER and the doctors confirmed the AI's diagnosis.
Obviously, AI shouldn't replace doctors. But you'd be silly not to at least consult this (free) expert doctor in your pocket.
In recent tests ChatGPT outperformed doctors in diagnosing medical conditions. It scored 90% compared to doctors' 74%. When I get blood test or MRI results now, I ask AI to explain them in plain English and suggest questions for my doctor.
In the near future AI will give a “second opinion” on every medical scan and doctor’s decision anyway. You can live in the future by consulting “DocGPT” today. Hello, AI early warning system for your health.
My best advice: Just start. Ask your chatbot of choice to explain something you've been curious about. If you’re not sure what to ask, tell AI about yourself, your work, your interests, and let it suggest ways it can help.
Think of it like picking up a golf club for the first time. You'll feel awkward and maybe even grip it wrong. But stick with it, and you'll get the hang of it.
Pro tip: Think of AI as a brilliant but literal-minded employee. You wouldn't tell a new hire “Make this better." You'd explain specifically what needs improvement. Instead of "help me write an email," try "write a professional email to reschedule a client meeting, emphasizing how much we value their time."
This gets to the heart of "prompting" or how you talk to AI. AI models are like a flashlight in a dark warehouse. How you phrase your question is like aiming that beam. Sweep it too broadly and you'll just get a dim view of everything. Focus it precisely and you'll illuminate exactly what you need.
The clearer your prompt, the more useful the response you'll get. We can dig into prompt engineering in future Diaries if you’re interested.
Big picture: Whether you're mastering Spanish, helping your kid grasp geometry, planning the perfect anniversary dinner or a vacation, you now have a brilliant advisor available 24/7.
AI is a new superpower. Those who start mastering it now will have an incredible advantage.
I believe AI will fuel the biggest small business boom in history. We're entering an era of "extreme leverage" where one or two smart people with AI assistance can build something extraordinary. The next billion-dollar company might start with someone like you, sitting at home, working with AI to solve a problem you deeply understand.
And yes, teach your kids how to use these tools. In the age of AI, even homework must evolve. Leading educators like my friend
are already designing AI-based assignments that test understanding rather than memorization.This is just the beginning of our AI journey together. The
will keep you on the cutting edge of what's possible. But for now, your mission is simple: spend 10 hours with AI. Jump in and get your hands dirty. Ask it questions. Give it tasks. Learn its quirks.The future is here. And it's not about AI replacing human intelligence. These tools amplify our potential.
Let's make the most of this amazing new productivity tool, my fellow Rational Optimists.
I was blown away by the hundreds of emails you sent in about learning to use AI. And I want to hear more from you!
What do you want to know about AI? Excited for AI agents… wondering how to give your kids a head start in this new world… worried robots will steal all the jobs? Write me a note in the comments section below.
Encourage your friends and fellow Rational Optimists to get more from AI by clicking the “Like” and “Restack” buttons below.
Stephen McBride is a co-founder of the
.
Hard to write something that most folks can find valuable when it comes to actually using AI, but this is a good starting point man. Love it.
I would love to learn more about how to draft queries to AI.