Yeah, go in irritated about all this discussion re:your weight and take it out on your opponent!
Don't worry about developing a new throw or whatever, feel confident with your sweeps. Most of Judo tourney game is avoiding penalties and ippons-which is kind of dumb but that's how it works. Be really aggressive and focus on grips and kuzushi and sweeps, the judges like that cause you'll be moving around alot and attacking your opponet's balance.
Is this your first competetion? Judo or otherwise? I think it helps alot if you don't look at anything that's going on around you, especially watching the fights before yours as it tends to get your heart racing. Sit as far away from the action as you can and stay detatched. If you have a specific gameplan, keeping your emotions in check helps you stay focused IMO