Answer 1

First you learn basic of that programing language which you want to learn then always try to practice the things you learn daily means try to do short programs if you stuck then take a help form google. Also when you taking help form google don't copy paste fisrt try to understand what is that then use.

Answer 2

Don't worry about remembering. You'll never remember all there is to learn. But you can always reference the material you have learned. Practice by repeating what you have learned. In a project. If you are not grasping the concepts then ask for an explanation of said concept.

Answer 3

Practice