This is an awesome and heart-warming question. Tsuyoku naritai!
In Julia Galef's book The Scout Mindset, she talks about how attitude is usually more important than knowledge.
Knowing that you should test your assumptions doesn't automatically improve your judgement, any more than knowing you should exercise automatically improves your health. Being able to rattle off a list of biases and fallacies doesn't help you unless you're willing to acknowledge those biases and fallacies in your own thinking. The biggest lesson I learned is something that's since been corroborated by researchers, as we'll see in this book: our judgment isn't limited by knowledge nearly as much as it's limited by attitude.
It sounds like you have a great attitude. I suspect that you're a much better rationalist than you claim to be.
Some thoughts on your original question:
Broadly speaking, I'm in favor of defining Rationality as systematized winning.
To become a better rationalist, you have to have something to win (or something to protect).
So you need a goal that isn't directly "become a better rationalist". This goal could be to learn a new skill, accomplish some simple task, or literally anything else.
Some suggestions:
Attempt to complete the goal, using what you've learned. Take notes. Reflect. Get better. Iterate.
Remember, the goal is to cut the enemy; the Art is not to be studied solely in isolation.
I’ve heard good things about the Guild of the ROSE, a virtual community made by rationalists to help each other level up in practical success in everyday life. You may want to look into joining them.
If your head is full of concepts but you haven't applied them, there are a few things you can start practicing - easily, right now - to begin living rationaly.
Let me know how it goes. All of these can be done on the order of minutes.
Late to the debate, so just a few notes:
Some things are way more important than others. If you are currently doing something really stupid in your life, fixing it is more important than learning a list of 1000 cognitive biases and rationality techniques.
It is much better to have 5 techniques that work for you and use them regularly, than to memorize a list of 1000 techniques and actually never use them.
Make logs. (And make them simple.) For example, if your goal is to exercise regularly, put a circle in your calendar whenever you exercise, or something like that. This gives you quick feedback whether you are actually doing things, or just lying to yourself.
Think about how you reward or punish yourself. (Read the book Don't Shoot the Dog.) Punishment, including self-punishment, is almost always the wrong approach. Why? Because you indirectly punish yourself for noticing the problem, and for trying to overcome it, which is the opposite of what you would want to do. Partial successes are a reason to celebrate! (Ancient wisdom says: "All you need is love positive reinforcement.")
Your body has a huge impact on your mind. Getting enough sleep, exercising regularly, getting enough sunlight, seeing your friends... are powerful (indirect) rationality techniques.
Well…
Right now, being ‘a rationalist’ could be said to be a massive part of my identity, at least judging by the absurd amount of time I’ve spent reading posts here, or SSC/ACX, and in a few other places. Yet, I’m still a mere lurker unfamiliar with most of the local customs.
But it’s not what matters. What does is that I’m a terrible rationalist.
You see, rationality takes practice. And reading stuff on LW isn’t practice at all. If anything, it’s just a great way of filling my brain with a lot of useful concepts, and then either blame myself for not using them, or use them for something entirely unrelated to their normal purpose. Often, to make myself feel worse, and think worse.
As the saying goes, rationality is a martial art. Learning it by reading the rules, or by watching other people apply the rules, is about as effective as developing one’s muscles by watching sports on TV.
I know of the CFAR, and of various related groups, meetups for ACX readers or for other people, etc. But, apart from ACX meetups, which aren’t about being better rationalists per se, I don’t have easy access to any of those, or certainly to a general environment which welcomes this. You know, not being in the Bay Area and all.
And yet, I want to be more rational as much as anyone who’s been lurking here for five years wants it, and given how depressed I was until very recently, I probably badly need it, too.
I’m not sure what kind of answers I expect, but, like, how can I push myself to learn more, and especially to practice more, and ideally to actually use rationality to improve my life?