Depending on how far away the tournament is you'll need to adjust your training. If your far enough off, then that is the time to fill in the holes in your game, and learn new stuff. As it gets closer you want to develop a game plan that works to your strengths, and train to always bring the match back to your game.
For example, I'm a guard guy, so I will work on good sprawls and stuffing or reversing takedowns (because, even though I like working from the bottom, I don't want to give up the 2 points), and work on aggressive guard pulling. I will also work isolation drills as pointed out by an earlier poster, but with a focus on regaining your game from a worst case scenario (ex. I get taken down and have my guard passed, now I have to regain guard). Also, I would pick my strongest sweeps and subs from the guard and drill the hell out of them.
As it gets closer yet to competition time increase the intensity of your training. You want to be able to go full out for the time limit that the tournament is going to give you, plus a little (because of the stress of competition makes you more tired than in training). So, as a brown belt I know that my matches will be 8 minutes, so I try to train high intensity for 9 or 10 minute intervals, with short rest periods in between. So, say I'm doing an isolation drill with the guy starting cross side on top of me. I drill it for a full 9 or ten minutes without the usual settling and resting you do when you are actually rolling. If I escape (pull guard or reverse him), I immediately go back to the bottom and continue, if the other guy taps me, the same was immediately start again and I go for the whole 9-10 minutes. Short break, then switch with him on bottom and me attacking from top.
Last week or so your gonna want to back off on intenstity and just roll smooth. Don't spend time learning anything new, just roll with good flow.
Things you could focus on to help develop a strong game (you can rep this stuff):
Your favorite sweep
then, favorite sweep, guy defends, back up sweep
then, favorite sweep as set up for sub
then, favorite sweep, following with favorite sub from top
Then, favorite sweep, guy defends, back up sweep with finish from top
From standing, aggressive guard pull, right into favorite sweep
etc.
Favorite guard pass
then, favorite guard pass, guy defends, transition to another pass
then, favorite guard pass, and sub from side control
then, favorite guard pass, transition to knee on belly
then, favorite guard pass, transition to knee on belly, then sub
then, favorite guard pass, transition to mount
then favorite guard pass, transition to mount, then sub
from standing, favorite takedown, transition to guard pass
etc.
One of the best things to do when preparing for competition, I have found, is what we call the gauntlet. As a Brown belt my match will be 8 minutes, so I find 4 guys and they rotate in fresh every minute for 8 minutes with no breaks. I go as hard as I can, and if I get tapped then we stand back up.