It's just like learning trees. Learn one, and then the next day add another.
Playing in a praise band is helping me. Sometimes you get just chords and words, sometimes you get a lead sheet with a melody written out plus the chords. 90% are in key of D, occasionally you see G and more rarely A. So you expect to see the I, IV, and V7 a lot and you learn them quickly.
But then they throw in weird ones I don't recognize, and I have to look them up and figure them out (plus the inversions). I'm sure if I really knew any theory they would be obvious, but looking them up one at a time is adding to my knowledge in a useful way.
There is a book called Learning to Play from a Fake Book (or something like that) that may be helpful.