Lose 65 pounds in 6 months?

I want to get into shape by next school year so people stop calling me fat *** and shlt. it really makes me mad when people say that stuff but I just suppress it. My friend lost 100 pounds since last year and he's highly inactive, but he looks amazing now. I asked him how he did it, but he just said he cut out soda, fast food, and red meat. I can deal without soda, but I love red meat and come on, everyone just doesn't haven time once in a while and eats fast food. I put on A LOT of weight this year 25 pounds. I'm 6' and 237.6 pounds and I want to be 180. I've tried dieting before and failed. So I'm wondering, does anyone have any good tips to keep me motivated? I'm planning on just working out a lot, drinking more water (even now I'm dehydrated and can tell), and cutting back on how much and what i eat, like eating a sandwich instead of nachos for lunch. What might help keep me motivated? Other than hating the way I look?