learning correct technique

Question
Matt,
    I play volleyball with a bunch of guys every day for about an hour, we play on dirt/grass courts, and we have no coach and have not been taught how to play. I have played for about a year, and I have tried to find out as much as I can about correct spiking technique (my biggest problem).
I've read about the different techniques but I can't seem to get a consistent swing that has real power. I'm 5'8" 160lbs and I have a 26" vertical. I have been focusing on contacting the ball higher (didn't use to) but I still don't have a consistent attack. My shoulder is prone to getting sore the way I spike, so I've been doing some rotar cuff exercises to see if that helps, but basically I need to learn correct technique. Somehow I don't seem to have the mechanics all together. If you can help that would be great.
P.S. I don't expect to crush the 10 ft line, but I'd like to learn to hit hard and deep consistently at least.

Answer
Matt,

My guess is that you are hitting the ball to far behind your head.  What are you looking at when you swing? Here is an exercise to help your swing.  Use a tennis ball, take an approach, swing and release the ball. This will help you see where you need to make contact with the volleyball.  When you swing at the ball......see the ball, if you cannot see the ball in front of you you will not makegood contact AND hurt you shoulder.

If this doesn't help call me at 347-612-5881 EST.  If you are from California REMEMBER there is a 3 hour difference.

Good luck,
Steve