When you're training hard you want to eat about an hour or two before your workouts and again immediately afterwards. Your snacks should include both carbs and protein to help restore glycogen levels in your muscles and repair muscle tissue. A post-workout snack might be a bagel with salmon and cream cheese, or a tuna and pasta salad.
For the rest of the day, eat small meals at regular intervals of two or three hours, with the aim of having some protein with every meal. This way you keep your glycogen levels topped up and prevent your body from breaking down and using the proteins that you need for muscle building.