Help me make a Fitness/Diet Plan?

Im 16 and as of the new year here is my diet plan. I wasnt ever overweight or anything but i knew i wasnt eating well and im getting to the point where snack foods actually effect me. So ive basically gone all natural. This means no packaged snacks like chips etc, and no unnatural drinks. I basically drink water, lots of tea, milk, juice, etc. Absolutely no soda, energy drinks, or coffee. Part two is to only eat until you arent hungry anymore. Any good nutritionist says you should only eat about your fist size of food for each meal. Thats because anything more gives you the feeling of being full bc your stomach is about the size of your fist. So basically eat naturally and only eat until your full. Healthy snacks between meals are ok of course.