Taking a good, solid grip on a golf club should be a repetitive action dictated by feel and muscle memory. It's the first lesson most players get, and for the best or at least the most experienced players, it becomes second nature like breathing. There are a few queues, visual and tactile, that you can use to make sure you are gripping the golf club properly before starting your backswing.
Taking the Proper Golf Grip
Shake hands: The first thing you need to do is place your left hand on the grip of the club (right hand as a left-handed player). Reach out toward the club the same way you would if you were shaking hands with it. Your thumb naturally fits along the top of the shaft, the grip lays across your palm and your fingers clasp gently but firmly around the handle.
Overlap: Simply place your right hand naturally over your left either overlapping or interlocking your right small finger and your left index finger. (Again, reverse this if you are a left-handed player.)
Feel: Now that you have the club grasped in both hands, feel the weight in your fingers. You should be able to control the movement of the club head very well with your fingers rather than attempting to hold it inside the palms of your hands. Your fingers have much more dexterity than your fists. You should feel your thumbs along the top of the shaft and your fingers, particularly your top index and second fingers loose against the bottom of the grip. Make sure you hold the club only as tightly as it takes to keep the club from flying out of your hands. Too tight a grip puts tension in all the muscles of your hands, arms and shoulders.
Check Your Vs: The "Vs" made between your thumbs and index fingers on your left and right hands should be pointed at your right shoulder (left) and chin. This is an easily controlled and manipulated neutral grip. If they are pointed further right, you've taken a strong grip and setup for a hooking shot to the left. Further left, you've weakened your grip setup for a fade or a slice to the right.
One last look: Once you've verified your grip and take your stance over the ball, take one last look at your target, pull the trigger, and you're off to the races.