What you use to fuel your body is just as important as how hard you push yourself during training. Remember to have healthy, whole foods on hand. I don't want you to count every calorie or weigh every morsel on the scale, but I do want to make sure you eat what you need to get through your workouts effectively.
It's also important that you eat fairly often. Try to eat at least five meals each day: three solid meals, and a couple of good snacks. They don't have to be big, but providing your body with a consistent supply of protein and other nutrients will help your muscles recover, repair, and grow!