You haven't given us much to go on. Which scores are your lowest? Appearance, Taste, Tenderness? Also, which type of competition? KCBS, MBN, ICBA, ??? Which meats?
My advice? Spend the next 30 days digging through the archives here. I'd be willing to bet a whole dollar that almost any question you'd ever have about competition BBQ has been answered somewhere here already.
You haven't given us much to go on. Which scores are your lowest? Appearance, Taste, Tenderness? Also, which type of competition? KCBS, MBN, ICBA, ??? Which meats?