I am 12 and I workout. I want cut but strong muscles. I need any tips/advice I can get.?

Your best bet is to consult with a personal trainer, even if for only one evaluation to give you a set of exercises. If you eat properly in conjunction with exercising, you should have some good results. Doing weights while still growing will be easier to build muscle than some older starting for the first time. Just don't overdo it!