Best way to go vegetarian?

To say meat plays large part in my diet would be an understatement. Honestly every meal includes some form of meat. I want to go vegetarian and then hopefully some day, vegan. For both ethical and health reasons. Anyone out there who's gone vegetarian, how did you do it? Did you do it in stages, so you gradually weened meat out? Or did you just go cold turkey? I've actually done that, and then after the first week I wanted something to eat, so I ate a hamburger. When I'm eating meat, I feel upset about it but it tastes so good. So how can I do it? This is the summer before my freshman year in college and I'm going to Oberlin so the dining services are really vegetarian and vegan friendly. Help!