I need help on my football D-End Position?

I'm a sophmore playing highschool football d-End i'm 5'9 and way just about 200 maybe little more. I have good experience in middle school and was out my first year in JV due to injury. But Im fast and explosive and strong but need more in me. I try go gym alot ,,, but what should i do at gym thatll make me better at my position specifacally and any more tips to get better? hopefulyl i get taller a little over summer to 5 10