Tell Yourself You Love You
Look in the mirror and tell yourself that you rock. You're beautiful, you're unique, and your body can do some pretty amazing things. Start by trying it just a day. Smile at yourself in the mirror instead of frowning. Strike a hilarious pose. Rock out to your favorite playlist first thing in the morning in front of the mirror and love the skin you're in.
If you waste your life thinking 'I'll do this once I'm skinny," or "I can't do this because I'm not thin enough, not pretty enough, not fashionable enough," then you're going to have a lot of regrets once you miss out on your youth. You can do whatever you want, don't let anyone tell you otherwise.
Hell, if you can get out of bed in the morning, you're a miracle.
Treat Yourself with Respect
Sure, its fun to make fun of ourselves from time to time (I'm always late, my shoes never seem to match my outfit, and my hair is nearly always a train wreck) but you also need to give yourself a break. If you keep calling yourself names and putting yourself down, chances are it will stop being a joke and you'll just start believing it.