The best way to help improve your swing is to use a personal instructor if you can, but if there is not one nearby, or you want to try it yourself, then virtualhitting.net may be your answer.  Here is a question from my FAQ section concerning my guarantee.

Do you guarantee that this will improve the swing?

No, I can’t guarantee that using virtualhitting.net will improve a player’s swing.  However, I will refund your purchase price, within 30 days of purchase, if you are not satisfied with this service. I don’t believe any instructor in the world can guarantee that your player will hit better in game situations.  I do believe, however, that if you are taught correct fundamentals and work the drills on a regular basic that you will improve!