The only thing I can add to what Flesh said is make sure you try to fill in any gaps in your score sheet. For example: if you complete the following problems 3000, 3100, 3300, 3400, 3500. You should go back and try to get 3200 unless it seems a lot harder than one worth more than 3500. If that is the case then give everything you have to try to get that problem worth more than 3500.
If the problems are graded accurately and there aren't many major height differences then the winners in each category won't usually have many gaps in their score card.
Here is an example of what a typical abs comp looks like.
