Have you ever considered entering a writing contest? If not, why not? You have nothing to lose and everything to gain. Maybe I should qualify that a bit. If you enter a no-entry fee contest, you have nothing to lose. If the contest requires an entry fee, you still have something to gain. It's up to you to determine if you're willing to risk losing the entry fee in the event that you don't win.
So, how are you going to decide whether to send that $5, $10, or even (gulp!) $25? You need to look at the prize money being offered and another factor. Is the contest a small one or a big one? In other words, are you going up against a hundred other people or ten thousand? The bigger the contest, the greater are the odds that you won't come out on top. Some contests consider all entries as regular submissions to their publication, so even if you don't win the contest, you might have your work accepted.
My suggestion for entering contests is to begin small and work your way up. Most state writers organizations run contests, and some districts within a state will also have an annual contest. Or even a local contest that your community newspaper runs would be a good starting point. A mountain climber doesn't climb the Matterhorn on his initial climb. So, why should writers be any different?
Just like sending your work to a magazine or anthology, entering contests requires following guidelines carefully. If you ignore the guidelines, there's a good chance your entry will be tossed before it's even read. It's definitely to your advantage to follow the guidelines to the letter.
So where do you find these contests? Writers newsletters that include markets will announce new ones as they come along. You can also use keywords like writing contests or contests for writers in a search engine.
I have contests on my mind since my state writers organization opens theirs April 1st. Winners are not announced until early October, and the entry cannot be published prior to then, so that means writing something new or something not published already.