Economy of movement
The best thing to do with your golf swing is to reduce unnecessary movements. Think of it as energy conservation, since all of your energy is supposed to be focused on hitting the ball and not wasted on awkward movements that cause slicing and other problems in the first place. Get back to the basics and incorporate only the movements needed to hit the ball dead center. This should lower your handicap by 7-12 strokes in no time. With more practice, you will hit par or better every single time. However, that is only if you do practice.
To learn more about the golf swing, the most obvious thing is to receive instruction in an actual golf class. These classes would have equipment and instructors that can help you achieve perfection as long as you have the determination, discipline, and money to do it. Enrolling in such classes does require a fee, so you do need to be earning quite a bit before you can actually think of getting into it. However, you can learn a lot if you do.
Others would try to find information over the internet. This is quite convenient, but the information gathered can be quite conflicting. As there are many different ways to hit a golf ball, experts are divided in what is the best way to improve your golf swing. Your job in this is to find out what is best for you. Every golfer has a different body, so not everyone can adhere to the same swing.
By being able to adjust to your configuration, you can improve without having to break a back or hip to do it.