What separates a good player from an advanced player?

[GoodOL]

Hello all. I've been playing poker full time for close to two years....anywhere from $3/$6 to $10/$20 (4 tables, 10 seated mostly) and have been consistently winning. However, I only made $20K last year (I bounced around sites, propped,....bad runs, learning curve, bad play etc....). I have played better this year but still have only made $30K so far. I can't tell if I'm not playing optimally or if it's just bad luck. My winrate is a little less than 1.0BB/100 hands (not counting rakeback).

I am a 15/8/1.6 player. I've read all the poker books, some of them several times. I am not a regular here, but have read many posts. I understand many advanced concepts. I've played many hands.

I play against some 17/15/2.2 type players and notice that they are the toughest opponents (and therefore think maybe I should be playing as they do). However, I can't help but notice these players making, what appears to be, bad plays (i.e. three betting my UTG raise with something like ATs then calling me down when they miss)....but, they seem to consistently win and to wreak havoc for me.

I guess my question is...what might I be missing? I know this is a difficult question to answer...I guess I'm just looking for some input. Am I playing too tight and conservatively (I've tried playing looser, but it always seems to end up killing me)? Should I be playing 6max games? What do you think separates a solid player from an advanced player?