Great skill improving technique that I use:

Question

When programming, sometimes we use built-in library fumctions.
Sometimes, before using a built-in functions, I try to write my own similar function.
It's really challenging.
Not all functions are easy to do, But just by trying you gain something.

Answer 1

I recommend implementing some ides from Coding Ideas 2 (https://play.google.com/store/apps/details?id=com.alansa.ideabag2). It really makes you think about the problem.

Answer 2

Good idea...