I've been playing baseball since the age of 6, and after about 10 years I can tell you I have received TONS of advice from hundreds possibly thousands of sources about hitting. I have been to at least 15 camps and over 20 private lessons not to mention the teams I have played on and the advice I have received from coaches and players on those teams. I can tell you hitting is much easier than what most people make it out to be. I think I have finally perfected the swing now and I can tell you my mechanics.
1. Start with a wide base but not too wide that you feel comfortable. Figure out a happy medium between your base and your step. Make sure your step doesn't exceed a foot, in my opinion. You might see players like dustin pedroia, but you'll also see players like albert pujols. I prefer a wide base. It'll give you a lot more balance and ability to hit the ball, without losing any power. (No momentum is not what gives you power)
2. When it is time to step bring your hands slightly back, but do not wrap them back, or twist your upper body with your hands.
3. Make sure at this moment you are recognizing the pitch, if your going to swing or not, and where you want to hit the ball this might take time to get used to. Once you have identified the pitch, await as long as possible to hit the ball. The longer you wait the more bat speed you will have towards it and the more time you will have to see the ball. This also might take a while to learn. Now when the time has come to swing start by firing the back HIP not your foot. Rip that hip, while still keeping hands back and let the tork of your hips going compel the bat forward to the ball. Obviously make sure you have a straight path to the ball, and your not looping your bat or extending your hands. Your hands should be tight when hitting the ball, and not extended like so many people tell you to do. After contact just follow through.
Tips:
**Make sure you fire your hips and not just twist, get as much power as possible through this without over doing it and losing focus of the ball.
**You should let your lower body do the work, the arms and wrists are just there to move the bat and hit the ball to where you want. Your lower body is your power, your upper body is your control.
**Have a low stance, not too low, but low. Make sure your knees have some bend to them and have a wide stance. Have a small about 2 inch step straight step. Not towards the ball.
**Make sure your back is straight majority of your swing, don't bend it around. You will lose power and stability doing this. On a low pitch even though you are already low, it is ok to bend your knees a little bit to get to the ball, not saying too much but a little bit. Don't go from down to up, in other words don't start low and go high. If you feel like you have to go up for a ball, it's a ball. Don't swing at it and stay low.
**Remember hitting takes time, don't fall back into what is familiar just because your not used to it. It takes repetition. Dry swings and BP are the best tee work isn't so great. Watch yourself in a mirror, and practice the steps, but not to literally, just really make sure your firing those hips, keeping those hands back, and let the hands go to the ball, keep hands not to tight, but even with your body and not out front.
Hope this helps a lot. I know it has helped me a ton over this last year. Remember perfect practice makes perfect.
Auz