First things first:
Get rid of that shirt you decided to keep last year because you thought you'd wear it. YOU DIDN'T.
While you're in your closet:
Give your friends their outfit's back that you causally kept forgetting to return. You didn't forget, you're just lazy A.F.
Throw away the Halloween candy you've been hoarding for six months. You can keep the Valentine's Day chocolate to get you through this years spring cleaning though.
In other food:
Remember all of those drunk snacks you brought into your room? Probably not, but those plates are stacking up and I think I saw something move. Take 'em to the dishwasher.
Speaking of movement:
Something just moved in the corner over there. Oh, it's just a massive dust bunny. Clean that s**t up.