The great thing about singles events at Valentine's is that everyone is in the same position - it's a level playing field. A big problem people confide to me is that they walk into a singles event believing everyone else is more confident and happy than they are. Believe me, 99% of the people at such an event will feel just as you do - a little nervous and insecure.
Even if you're not feeling confident - pretend you are! Check your posture - make sure you're not shrinking your body down like a nervous little wallflower. Instead stand tall with your shoulders back. People are attracted to confident-looking people so you're likely to get more attention.