Try to eat at least 4-5 meals per day... so the calories you burn in a day minus 500... take that and divide it by 5, that's kind of a 'guestimate' of how much you should eat each time...
Also, try to have some sort of 'clean' protein with each meal... Chicken, Turkey, Tuna, Cottage Cheese, Yogurt, etc... are a couple of examples....