Stop keeping all this stuff in your closet that you don't need. You need to pick and choose your battles with the clothes you're wearing. If it doesn't flatter you or you never wear it, toss it right now.
Now is the time to decide what you really need in your closet. What does your closet say about you? Are you put together in your outfit choices or do you throw stuff together?
You need to think wisely with the contents of your closet. What makes you feel confident and comfortable. You don't need clothes that don't make you feel good about yourself or are painful to wear. The scratchy turtleneck that you never ever wear because it is so dreadful MUST GO. NOW.
Those outfits that you only wore once for one event, it's time to lose them! Everything you own that you keep saying, "Oh, I'll maybe wear it again eventually," and then you list possible events you can wear it to...It's not happening, move on.
Think about where you are in your life. If you're a college student about to go into the world and get a real job, probably off in a cold office cubicle somewhere, do you really need a ton of crop tops or cut-out shirts? They won't help when you're interviewing for your dream job. Try to at least start building your collection of business casual or professional clothing. Get some suits or at least some slacks.
Try to keep your clothes aligned and organized. The easier it is to find things, the more you can wear it. You're not going to be able to wear clothes you can't find. Keep things on hangers and shoe racks! Don't angrily stuff things into the back of your closet or throw stuff into little piles on the floor.
Also, redefine your definition of keeping things for sentimental reasons. If grandma and grandpa love to send you a million t-shirts, do you really need to keep them all for emotional value? You don't need 500 t-shirts, especially in an area with changing seasons. You can keep some for the warmer weather and the gym, but that's it!
This is the time to reorganize your closet the way it needs to be! Summer is almost over and it time to clean it out in time for fall!