awww, baby *huggle* why are all the best kids the ones who hate themselves?!
Okay, it's really easy to ignore, forget, or disregard words you read on a screen so I'm telling you now; This advice is based in my own experience. I truly believe it works for everybody because it's logically and psychologically sound.
You can change the way you think by creating an environment in your brain that allows for change. One of the best ways to do this is look at something that's a problem and, by baby steps, changing it into what you want it to be. But be careful to remember that sometimes something kind of unrelated might actually help with that problem.
For example, I wanted to get skinny but I wasn't willing to exercise only for the sake of slimming down. But when I started doing push-ups (which I need to start doing again because my arms have reduced themselves to noodles XD), my goal was to get stronger. When I was doing laps around my driveway (which I should also start doing again for the same reason), it was to improve my endurance. Those together paved the way for when I got an elliptical - and almost immediately started losing weight.
Also, look yourself in the eyes in the mirror and start telling yourself, over and over, the opposite of why you hate yourself. If you think you're ugly, tell yourself you're beautiful. If you think you're dumb, tell yourself you're smart. Eventually, if you hear something enough times, you'll start to believe it. That's why you allowed yourself to believe the lies in the first place.
Last of all, I want you to be encouraged; I'm praying for you.