And how did you, advanced Linux user, get to the stage your at now?
Incrementally over time by reading the documentation and/or manuals of the commands I need to run and looking up how others solve the problems that I need to get other ideas about things (even, periodically, for things that I already know how to do to see if anyone has found a better way to do it or if a new tool has come out that helps). And trying things out/experimenting with different ways of doing things to find out what works well or not.