Hi, i'm about 5, 6 and roughly 110 lbs. i've been trying to gain weight, i eat plenty of healthy food most of the time and workout. what els can i do?

Weight gain: Gaining weight is excess calories. Being 16 you're burning calories like a furnace. Muscle gain is the desired goal, increase in total calories is needed. Up protein, carbs, n maintain fat content (don't lower or raise it) exercise should be focused on beginner weight training, and a trainer is highly recommended to avoid injury. Go slow and don't rush, proper technique trumps heavy weights.