[header] How to go on a school field trip to the beach [title] The month before (if you know this much in advance), start working out a little. [step] Do 10-20 sit-ups per day , 30 jumping jacks or even a jog with your ipod or iphone or dog. [title] Eat healthy. 
[step] Fresh fruit and vegetables are the way to go, and check what's in season, like berries. If you know you are going to break this rule, eat semi-healthy things in small amounts such as dark chocolate (70%-80% cocoa) for a fix.