How do I lose a few pounds for prom?

Prom is just around the corner and I wanted to look my best for when I pick up my date. I don't have money for a new tux but I tried on the one I used last year and I looked pretty damn good lol and I tried it on today and its a little snug especially around the midsection. Can you give me some advice on what I could do to shed some pounds off. Thanks