Unfortunately there's no consensus on what's best to eat, and everyone is different. I'd read a bunch of books on nutrition, divide by two, and see if I felt good. It takes a lot of experimentation to see what suits a particular individual. There are some generalities, such as eating a good variety of colored vegetables, getting enough but not too much protein, drinking plenty of water, getting enough fiber, getting enough of beneficial fats and cutting down unhealthy fats, but you are the only you. Get studying and see what sticks.
http://www.livestrong.com/article/453941-a-healthy-diet-for-a-14-year-old-to-eat/