Are you playing well and not winning that big tournament? Frustrated? If you want to win, stop playing. Let me get there before you toss this ostensibly absurd advice aside.
I've recently anaylzed my poker successes and failures over the last several years and have come to one simple conclusion: I play significantly better after taking an extended break. Invariably, I always come back to poker because I love it. And after a hiatus, I really enjoy playing again. I tend to be more focused and bad beats roll off me with greater ease.
The only emotion you should be bringing to the table is a love for the game, anything else is just likely to impair your judgment and your game. Your mind needs to be clear and sharp. Too often I have played bored, impatiently, or just uninterested. Perhaps I was just playing too much. Of course, experience is invaluable but playing fatigued or on tilt is just likely to cause you to develop bad habits. You'd be better not playing at all ... for the time being.
So, stop already. Take a break and come back refreshed. A happy, well-rested, emotionally stable and determined player is tough to beat.