I keep forgetting my lessons on coding, how do I remember them?

Answer 1

If its the basic part, like conditional branch, loop, etc practice will help
But if its about the keyword, built in method and function, the right way to type something (like anon/lamda function) keep a reference close. Tbh after few years programming i'm still struggling at this sometimes

Answer 2

You can remember any item of knowledge by systematically reviewing it with increasing time intervals:

1.) after one day
2.) two days after that one
3.) four days later
4.) 8 days after that
5.) ... [ad libitum]