I MUST lose my tummy!! ; P?

Alright, I'm 22 years old and I finally decided that this summer IS the summer when I'm going to have a flat stomach. I'm a thick girl : P but my tummy is the only place where I actually have excess fat. Among wanting to wear a smaller pant and shirt size, I want to get my belly on pierced this summer. So, I'm going to start my regimen of running for a half an hour 3 times a week, Monday, Wednesday, and Friday. On those same days, I'm going to do some ab work, crunches, etc to tone the muscles. Also, I'm cutting out soda completely (I did that for prom and found it very easy!! : P) and I'm drinking tons of water and I'm watching what I eat. Has anyone here been successful in losing their belly fat that can give me some more tips to add to what I'm going to be doing? Thanks!! : )