Training proper muscle memory in the golf swing can be a daunting task because many of the sport's motions are unnatural and are used only in golf. To gain the feel for a proper golf swing, it is often necessary to employ certain training aids that aren't allowed when playing a round of golf. The good news is that you don't have to build these aids; many of them you already own and can simply use them as training aids.
Easy Training Aids
Find an old club you no longer use a club that is broken. Break the head off the shaft and you can use the shaft as a training tool to help you fix your swing path toward the ball. Take the broken shaft and stick it in the ground approximately two feet behind the ball down your target line and another eight inches 90 degrees to the inside of that line. The shaft should be stuck in the ground at the same angle as your club's shaft is at address. Make practice swings and be certain the club travels to the inside of the broken shaft. This will help foster an inside-out swing path necessary for efficient shot-making.
To practice balance and weight position, take a 2x4 wooden board that is at least three feet long. Put this board on the ground and stand on it to make a golf swing. Once on the board, get into your golf address position and practice swings without falling off the board. In doing this, you will gain acute awareness of your weight's center and how to maintain your balance, which is critical to the golf swing. Balancing on the board will also reveal how your weight should be mainly on the "balls" of your feet and not toward the toes or heels.
To help make sure you incorporate an efficient back swing where the club stays low and to the inside of the target line, all you need is a spare tee. Approximately eight inches behind the ball down the target line and two inches at a 90-degree angle to the inside of the line, stick you tee in the ground so that it just barely sits above the grass line. You should practice making back swings so the club actually hits that tee going back. In doing so, you prevent your hands from lifting the club too early and increase the chances that you are making a good rotation with your core.
With a string and two pencils, you can build a great training aid to help your putting.The string can be of any length. Tie each end of the string to the eraser end of each pencil. On the putting green, stick one pencil into the ground behind the hole and the other behind the line of your putt. Make sure the string is tight and sits high enough off the ground for a golf ball to roll under. With the ball under the string, you can practice putting, using the string as a straight guide for your putter to take during the stroke. This helps build muscle memory for a linear stroke and encourages the putter blade to stay low to the ground.
With any club in your bag, you can generate the proper feel for sound, athletic posture. Take a club and put it against your back so that it mirrors your spine. Be certain you make contact with the club at three different points: your tailbone, the middle of your back and the back of your head. From this position, tilt at the waist, maintaining contact with the club at all three points. This gives the proper feel for your body at address and help you avoid getting too comfortable or 'slouched' in your setup.