Consistency to me is huge. You can be a great player but if you aren't consistent you wont make it to far. You don't have to win every game but getting last will kill you.

Another thing that goes along with the above. Tournament players vs the causal good player look at games differently. What always hurts me is I still walk up to a game and look to go through it (get to wizard modes) where the good players will find safe shots that are repeatable and will build points.