Most tourneys pay out close to the same percentage of entries (usually ~10% on Carbon). On one hand you can choose the ones that start at prime time which will have more players but typically be softer in competition because all types of players can enter. On the other hand you can choose the ones that start early/late which will have less players but be tougher in competition.

Personally I like to go for the primetime ones and play extremely tight for the first 3-4 levels or so. That can almost ensure that I won't be playing against any people that have just gotten lucky shoving for the first 10 hands.