To do well in a contest, your photo needs something that makes it stand out from the other thousands of entries. Unless the contest calls for it, don't do a lot of digital alterations to your image but do have an image that will be different. Instead of the basic quarterback throwing the ball, sunset over a pier, or cute puppy, try a photo with spectacular natural light, or an image taken from an unusual perspective. When submitting your entry be aware of any non-photographer friendly language in the rules, anything that would harm your rights with regard to the photo in the future. Be sure you read the rules and any fine print, consider entry fees and deadlines. Follow the rules completely.