2. Keep notes, in your log or otherwise, after every dive about what you feel you could have done better, or if you are having some gear issue. When I started out, and every time thereafter that I changed configurations, I made a point of trying to identify the one, two or three things that really bothered me most about a dive or series of dives, and then fix it for the next time either through practice or tweaking the setup.
Eventually, as you fix things one by one, you'll find that there's either nothing left, or what is left is really trivial. Especially in the beginning, it is an iterative process.