[stouset]

You should not be approaching chess as a memorization problem. Yes, as you gain skill and familiarity, your brain will pattern-match on particular aspects of positions but outside of openings memorization will not get you very far.

The things you should spend your time and effort on are tactics and positional play. Tactics will directly help with pattern-matching on situations with direct and immediate impact: taking advantage of forks, overloaded defenders, x-rays, etc. (as well as defending against those things). Positional play will help with pattern-matching on higher-level concepts: getting knights to ideal squares, understanding the implications of certain pawn structures, how to leverage bishops' strengths and weaknesses, maintaining rooks on open files, restricting your opponents' space and movement options, etc.

For the former, tactics trainers are your best bet. For the latter, I think books are probably still optimal. I'm a big fan of Jeremy Silman as an author, and Reassess Your Chess (4th Edition) is my personal favorite book for learning these concepts.

Studying openings should be done sparingly. Learning the basics and general principles of one opening system as white, and one each for 1. e4 and 1. d4 as black can be useful in helping you always get to midgame positions where you understand the basic ideas, but I wouldn't spend too much effort past that.