Judges do not know or care how many hours you slaved over your piece or how many people were involved or how many sacrifices you made. They work from a set criteria and in some cases see only 5 to 15 minutes of your work. A few of the smaller festivals return judging forms with the tape submission but a majority of festivals do not share criteria in that detail. Your best bet is to either view and analyze past winners or see if you can talk with prize winning producers via a website or e-mail address. Go to a festival - Participate as a spectator or even better, a volunteer.
Many festivals welcome volunteers.
If you've pinpointed a festival you want to participate in, find out if you can get involved. You may spend a year getting to know the festival but in the following year, you'll be ready to submit your work because you'll know all the ins and outs, how many submissions get accepted, and what the general level of competition. Lastly, be critical of your work but not hard on yourself. Whether or not you win a trophy, if you believe in your message and art and if it's made a difference to viewers, you are a winner. No cliche intended.