For starters, pick or fingers? Spock gave it a pretty thorough analysis, as we might expect from his username.
I’ll add that, if you want to learn fingerstyle, it helps to focus on players/teachers whose hands are similar to yours. Very important if you have small or large hands; might not matter much if your hands are average or if you just want to learn the basics. Theory’s important for improvising, as biotechmgr has noted, and also for working out chords on your own.