That isn't really a question someone can answer in one post. There are so many products and so much to use, and it's extremely dependant on the current condition of your car. When I had my VW, before every show I would wash and wax. Sometimes I would use a paint cleaner, sometimes I'd pull out the buffer and get some swirls out. It just really depends. Got any pics so I can help more specifically?
Judges look for cleanliness. Clean EVERYTHING. Get all the crap out of your car. Make it look like you didn't even drive it to the show. Make sure your mods are clean and not just thrown together. More mods doesn't equal more points. Just remember, quality > quantity.
Here's the last show my car was at before it was sold:
