The best thing you can do in that situation is get someone else to look at it! 9 times out of 10 a set of experienced eyes will be able to spot something you can't or something that you shouldn't be doing. You should always be looking for a different set of eyes to look at your flying to improve it from every aspect. Going to a contest also helps a bunch. Look over your score sheet once you get it and if you find a maneuver you thought you did really well, but got a bad score on, go to the judge who gave you that score and ask about it. It's impossible to perfect a pattern if you're the only one looking at it. You eventually get used to your own flying habbits and ignore things that you could be doing better.