In regards to improving your golf swing, the most important part of your body to focus on are your wrists. Your wrists are involved with starting the swing, finishing it and they determine how far the golf ball goes. If you do not have strong wrists, your puts will not be very accurate or go very far. So how exactly do you strengthen your wrists?
Outside exercise beyond golf can strengthen your wrists and help with your golf swing. One exercise that comes to mind is doing sets with a stress ball. Stress balls are easy to find at any toy or sports store. Doing a few sets with a stress ball every day is guaranteed to strengthen your wrists, forearms and hands. Another exercise that can be done almost anywhere are push ups. Sets of push ups strengthen your whole arm, and this includes your wrists.
Cross-training with other sports can also help improve your golf swing. Tennis, swimming and softball are all sports that use a lot of arm strength. Tennis, in particular, uses a lot of wrist strength and might be your best bet in improving your swing. You do not have to be a tennis pro to go out there a couple times a week and hit some balls. And I guarantee your wrist strength will increase within a few weeks.
In addition to unrelated exercises, drills are always helpful in improving your golf swing. There are many many drills available online and elsewhere. All you have to do is hop online and search. One example is to focus on following through with your swing, without actually hitting the ball. Stand on the golf course with your club, lean back on your back toe, take your club behind you with both hands and swing out in front of you, with the weight shifting to the front foot.
Do fifteen sets of this drill and see how you feel. There should be a mild burning sensation in your wrists. That means you are doing it correctly. This particular drill should eventually help you improve your swing.