I thought that I would say a few words about composition competitions as I have entered several over the past few months and have met with some success and have been disappointed with others. I hope that my viewpoints will be useful to other composers.
The two major resources I use to find out about competitions are the American Composers Forum http://composersforum.org/ and the Society of Composers http://www.societyofcomposers.org/. Both are membership organizations and the benefits are well worth the membership fee.
The next step is to be selective regarding which competitions you enter. Entering competitions can get expensive, as some have entrance fees and many require mailing multiple copies of scores. More and more competitions are going to online submission which saves duplicating and postage costs and I applaud this direction. It is bad enough that one sometimes needs to pay an entrance fee and many composers refuse to enter these contests because they say "why should I be supporting the prize money?" People running the competitions justify the fee by saying "it pays the costs of the judges and the administration of the contest." It is a personal choice as to whether you decide to enter competitions with fees. If I feel that my composition and the competition are a match, I will usually enter the competition even if it has a fee.
To determine if your composition and the competition are a match, see if you can find a list previous winners of the competition and try to locate their music. Google searching makes this fairly easy to do and it will give you a good idea of what the sponsors are looking for.
If you enter a competition, do not expect to receive feedback. I wish that feedback would be provided, especially if it is an annual competition that you have entered several times and not been successful. I recently experienced a non-placement in a competition that I felt sure that I would place. I did all the research and felt that my entry was very strong. However, it was not successful and the only thing I can determine is that judges found things more to their liking. One needs to realize that there are many fine composers entering the competitions and the judges will have their own personal preferences.
But if one is to further one's compositional career, one needs too realize that entering competitions are part of the process. It is easy to get discourage when one does not meet with success, but as the advertisement for the lottery says, "You can't win if you don't play." Just be selective, do your research, enter quality material, and do not take it too personally if you don't meet with success. If you keep doing it long enough, you will have success. Out of the dozen or so competitions I have recently entered, I have had success with two.
I hope that my experiences with competitions will help other composers navigate the maze of competitions. I wish all of you much success.