Figure out your goals, and then make plans for when you get off work to optimize for those. Working as a cashier doesn’t seem optimal for almost any purpose—maybe you could start by figuring out how to make money more efficiently, if that’s your goal?
Learn the major system or memory palace. This would let you store a list of things to think about or do when at work. It’s also quite easy to practice while at work, once you get the basics down. I’d recommend this first, if you really won’t be
allowed to write.
Solve problems. See what problem-solving methods work and which don’t. See what kinds of problems you are worst/best at, and become better at those. Math problems, world-modeling (prediction and underlying event deduction), and introspection are especially easy to do in your head.
Try to figure out why stuff around you is the way it is. (Why did that person buy that item?). Make predictions. Calibrate and get higher accuracy as well.
Introspect. Find out why you believe what you believe, and whether you should.
Don’t improve your rationality, do something else with your time.
Optimize your job as a cashier, as much as is possible. Figure out how to do stuff in the least time. Experiment when interacting with customers to see if you can get tips or interesting conversation. Get a different job (manager?) at the same establishment somehow. A useful problem will motivate you more than a non-useful problem.
Figure out your goals, and then make plans for when you get off work to optimize for those. Working as a cashier doesn’t seem optimal for almost any purpose—maybe you could start by figuring out how to make money more efficiently, if that’s your goal?
Learn the major system or memory palace. This would let you store a list of things to think about or do when at work. It’s also quite easy to practice while at work, once you get the basics down. I’d recommend this first, if you really won’t be allowed to write.
Solve problems. See what problem-solving methods work and which don’t. See what kinds of problems you are worst/best at, and become better at those. Math problems, world-modeling (prediction and underlying event deduction), and introspection are especially easy to do in your head.
Try to figure out why stuff around you is the way it is. (Why did that person buy that item?). Make predictions. Calibrate and get higher accuracy as well.
Introspect. Find out why you believe what you believe, and whether you should.
Don’t improve your rationality, do something else with your time.
Optimize your job as a cashier, as much as is possible. Figure out how to do stuff in the least time. Experiment when interacting with customers to see if you can get tips or interesting conversation. Get a different job (manager?) at the same establishment somehow. A useful problem will motivate you more than a non-useful problem.
Combine all these.