Answer 1

To retain knowledge it is best to practice and expand on it. Play around have fun with it.
Don't worry about getting things wrong, everyone will eventually make a mistake. The important thing is to learn why you made said mistake.
Also focus upon concepts over remembering syntax. That way you can know what you want to look up. There is no way around looking things up with the vast array of languages, libraries, and frameworks. There is simply too much for most people to remember.
So focus on the important aspects of programming, the underlying algorithms. Writing programs is a slow process a first until your comfortable, which only comes with time.

Answer 2

As I see it, there are two major components to progress: Actually writing code, and remembering what you learned.
Writing code is the most important thing. As a coder, you're a sort of translater. You translate specific real life problems into the abstract language a computer understands. This just has to be practiced. If you don't write a lot of code, everything else you try will probably be futile.
Apart from that, memorizing stuff can help. You need to remember how to write specific commands, how to use tools correctly. Sure, you can google them again next time, and for stuff you use only very rarely, it may make sense. But as a beginner, you'll waste time relearning stuff all the time.
The key to the second point is a good repetition plan. Let me link 1.) a tl;dr 2.) a longer explanation and 3.) a script which I use myself to simplify the process.
https://code.sololearn.com/W4P13u4XCmf9/?ref=app
https://code.sololearn.com/cBsq5rYsIB1A/?ref=app
https://code.sololearn.com/cL3QVCSUn0bp/?ref=app

Answer 3

The beat way to retain them is exactly the same way as is with spoken languages. Practice, practice and then practice more.

Answer 4

I want to collect this post as a green hand 😂