This is an interesting topic. First of all, I am assuming you are a very good contact hitter and have an idea how to stay inside the ball as well as stay through the ball (not roll over at contact). These are two things that are very necessary to improve power. Without them in place, you will probably only decrease your likelyhood of contacting the ball enough to impress scouts. With them in place, we can try a few things.
#1- Assess how well your backside transfers energy into the baseball. If you are getting good weight transfer, you are creating more leverage (power). If you are sitting on your backside and spinning, you are only using raw strength to power the baseball. A good idea of how to transfer your weight and get good pelvic snap, is important. Some good drills to improve this are "knee-pulls", walk-throughs, and over exaggerated long tee. (PM me for more detail on those).
#2-If you have good weight tranfer, then check your posture at contact and extension and be sure that you are not too upright (weight over front foot). Your body should be somewhere between 50-65 degrees depending on how long your stride is. The taller you are and longer the stride, the deeper the angle (closer to 50°). Staying back with your upper body once you have landed with your stride is very important to creating leverage (power) as well.
A good drill to check this is "freeze your finish" drill where you simply hold the finish of your swing and check the angle of the body posture. Also, extension drill will help to create a more consistent body angle through the ball.
#3-And this goes without saying...Learn what pitches you can drive and what pitches you need to simply hit. Too many young hitters try to drive every pitch rather than putting good swings on "pitcher's pitches" and pitches they can't handle as well. Once you learn what pitch location is "drivable", you can automatically take a more aggressive swing and really try to do something special with it.
Again, if you don't have a good "inside-out" swing as some would call it, then you are grasping at straws when it comes to improving power. You need to be inside the ball and have a good idea of how to maximize your bat speed through contact before worrying about building power. Think about most young MLB hitters and how as they get older and more mature, they turn into more of the "power hitter" type. This is usually because they really grasp the idea of how to "hit" for average and they learn to control the bat and then they work on adding power.
Good luck in your goals.
