Valmont, I feel the same way...I had to find out the hard way that it doesn't matter how much work you put into a track, if it's not hot, it's just not hot. Regardless, I can't just put a drumbeat behind a huge sample and let it go...lol.
Anyway, here's a good tip...I'm not sure if you have access to previous Beat This Contest or not, but if you do, go check them out. Check out the winning beats, the structures, the mixes and the general flavor. If not, just go to the home page and check out some of the tracks there. Most cats put up some dope work and that will kinda guide you on what people vote for. One of the main keys is to be yourself, make the music you like...don't make music molded after someone elses style. Thats about it. Let your confidence speak through your music.