I dont really prepare at all for tournaments. Other than i work on my putting a little more. In the tourney you'll learn a few things, Driving long isn't where the money is. "Drivin is for show, puttin is for dough"
One thing I realllllly try to work on in tournaments, is sticking to safety shots. If you play a safe round and try to end up as close to your normal score, you'll find that you'll do pretty well. When im stuck in the woods, I dont try crazy shots thru 1 foot wide holes in the trees or no crazy stuff like that.
Even if it means taking a stroke just so i can lay up a predictable putt, Im gonna play it safe so I shoot 1 over instead of 3 or 4.
If you play a consistant game, you'll see others who are trying to take highly improbable routes make the mistakes and lose strokes on you.
This is how I play in tourneys, and i find I shoot 2-3 strokes under my average game.