Work on your flexibility. Ideally, at the top of your golf swing, your shoulders should have turned 90 degrees so they are perpendicular to the ground. That's opposed to most amateurs, who rely mostly on their hands and arms to swing the club. In any golf tournament you see on television, there are professionals who turn their shoulders beyond that to generate more power and hit their drives consistently over 300 yards. If you increase your turn by as little as 15 degrees, you'll increase the distance of your golf shots.
Increase the speed of your club head by leading with your hips, because you'll hit the golf ball further if your club head is traveling faster at the point of impact. To prove this point, try throwing a ball using only your arms, keeping your hips and shoulders still. Then throw the ball again; but this time, use your entire body. Undoubtedly, the second ball travels farther. The way you swing a golf club is no different. You increase your club head speed at impact by shifting your weight first, thus creating a whipping action with your arms.
Start your downswing only after you have shifted your weight to the front foot by using your hips. By doing so, you increase the resistance between your lower and upper body, sometimes referred to as “torque." That will result in hitting the ball farther because you will have increased the speed of your club head. It all comes down to how flexible you are, and doing exercises to improve it will pay dividends by improving your game.
Practice these changes in your golf swing until they become second nature to you. Meanwhile, you can expect a lot of missed shots and frustration until you improve the timing of your swing. But sometime in the future, you will appreciate all of the work and your handicap will be lower as a result.