1) Be quiet until you see the scores and judge’s comments and have had a minute to distance yourself from the event. It looks very unsportsmanlike to bad mouth the contest, the judges, and/or your fellow contestants. I realize it’s an emotional process and hopefully people will forgive a moment of bad judgment, but it’s better if those types of things don’t happen in public. It just looks like sour grapes, and you may say something you regret.
2) Once you get your feedback, examine it for ways to improve. There are going to be throw away comments from judges that just don’t make sense. That happens, but the bulk of what you get back should be useful in helping you to score better next time. USE THOSE COMMENTS TO REDESIGN YOUR PIECE OR CREATE A NEW ONE. Don’t just ignore it hoping for a better outcome next time.
3) Read the scoring criteria. Did your dance have all the elements being scored? Were you good in some areas, but not in others? If you do something that is not being judged, you won’t get points for that regardless of how good it is. If you are weak in some areas, the stuff you did well in probably won’t compensate for that in such a way that you can place anyway. I have seen a lot of excellent dancers who don’t do well in contest because they don’t read the scoring criteria.
4) Look at the contest. Who is the sponsor? Who are the judges? What is the scoring criteria? What is the contest reputation? If you don’t have faith in those things, perhaps you are in the wrong contest. Check out a different one.
5) If you have done all that and still don’t have a clue about why you are not doing as well as you would expect, get a contest coach. Notice that I said “Contest coach”. Maybe your teacher is the greatest thing since sliced bread, but a contest is a specific type of performance. It’s not the same as doing a belly gram or restaurant performance. If you have an instructor who is not helping you to overcome your deficits, you need to consult with someone who has experience with competition. This is not dissing your instructor or mentor. This is acknowledging that different people have different skill sets and if you want what you don’t have, you have to go to someone who does have it.