The trick is to start with a few basic ones then learn more as you go along.

Know how to quit (C-x,C-c) & save (C-x,C-s).

Then basic moving commands: C-p (up), C-n (down), C-b (left), C-f (right), C-a (start of line), C-e (end of line)

I used just those for quite a long while before I learned others, and even with just those command I realized how much faster I was working, as it saved time from having to move my hand to the arrow keys.