Tastes vary a lot and what you may think is garish others think it looks great.
Probably the easiest way to pick up points is to have it clean, even the most awkward spots could loose you points if the judges were looking to downgrade your car. Other judges may be less so inclined to do that. I would go with a clean car and keep away from cheap flashy add ons. Learn and ask the judges what on your car they did not rate too highly. Listen and learn is what a guy told me once. Giving them a nice cool beer on a hot day can't do any harm either.