Since I work full time and go to school full time, my diet wasn't always the cleanest. For the most part, my "go to" foods are egg whites, oatmeal, lean turkey and chicken, protein shakes & bars, and many fruits and vegetables. Sometimes I had to settle for a small deli grinder or beef jerky when I was out and about.
I take protein powder, either Syntha6 or Gold Standard whey, as well as a multivitamin. I also added a "greens" supplement just to stay healthy and make sure that I'm meeting all of my vegetable needs.
Every workout is different for me. I try to incorporate various types of training into my workouts, such as crossfit techniques. I like to train intensely and go from one thing to the next with minimal rest. The last half of the contest was mostly core training. I trained abs 3-4 times a week. My workouts were mostly full body with high reps.
I did a lot of cardio during these 12 weeks. I would run 1-3 times a week for distance (sometimes 4,6, or 9 miles at a time). I also used the elliptical from time to time.