TL;DR

  1. Have some way to make your own money.
  2. Get in shape (or in better shape).
  3. Have an adventure.
  4. Learn how to make drinks.
  5. Learn how to cook respectably well.
  6. Get a few nice outfits to go out in, meaning more conservative and less douchey.
  7. Learn how to not sound like an idiot.
  8. Learn how to not look like an idiot while dancing.
  9. Make friends of a similar mindset who also differentiate themselves in cool ways.

Full article at Table Theory - any other post-college Sedditors should chime in with their own suggestions about what they did between semesters to become cooler and happier!