The final game of the tournament that I've been analyzing can be found in Annotated Game #5: First Sacrifice. As previously noted, that was a breakthrough game for me, being the first real (intentional!) sacrifice I had played in my tournament career. Since that tournament, I've had my ups and downs, but I've certainly played much more actively and looked for opportunities for attacking chess that would have been ignored earlier. As a result, I'm a significantly stronger player now, although I still have a long way to go in terms of my skills.
What were the reasons behind this mental breakthrough? It was not just one particular thing, I think. Study of a variety of well-annotated master games was certainly a key to breaking down my own internal prejudices on playing style and resistance to new ideas. I was also starting to lose my concern about ratings, which I think is a drag on anyone's real playing strength and a sure way to inhibit your growth as a player.
Finally, this was the first tournament I played in after taking up qigong practice, which involves slow breathing and internal visualization combined with physical exercises. In this last-round game, I sat there calmly the whole time while my opponent grew increasingly frustrated and excitable. On a more macro level, the increased calmness and objectivity that come from regular practice of this discipline (or related ones such as meditation) is a definite aid to calculation and assessment. Although it seems contradictory, this increased mental calmness has also allowed me to play a much more aggressive, attacking style of chess when the board situation demands it. My mind is now more open to what the position is objectively telling me is best to do, rather than me trying to impose my own desires onto the board.
Attitudes are in no way a replacement for skills, but I think for improving players (especially adults) it is just as important to identify what factors are holding us back or diverting us from the path to mastery. Un-learning things we erroneously believe or "know" is normally much more difficult and painful than new learning. If we are self-aware and honest with ourselves, however, it can be accomplished.