I'm speaking from very real experience
  1. Stare at your phone and pretend to text.
    People will think you're waiting for someone.
  2. Cling to the one person you sorta kinda know.
    You'll be able to tell when they start getting annoyed with you and try to avoid you, but cling hard. A friend! And you can mooch off of their friends!
  3. Drink a lot of alcohol.
    Sure you don't have anyone there to make sure you get home safe, but at least you're now the life of the party.
  4. Go to the dance floor.
    Just dance around on your own and hope that someone comes over to dance with you.
  5. Make eye contact with strangers.
    This one is hard when you're awkward, but if you make friendly eye contact, maybe they'll come talk to you.
  6. Compliment people.
    It's a conversation starter sometimes.
  7. When all else fails, take refuge in the bathroom.
    The toilet won't leave you, unlike fickle people. There may be some problems with this tactic if it's a single stall bathroom.
  8. Slowly and silently moonwalk out the door.
    Suggested by @dev
  9. Go home an watch Netflix
    Suggested by @danaschwartz