For a right-handed golfer, take your left hand and put it about a half inch below the top of the club. Wrap your left hand around the top of the grip and make sure your thumb is placed down the shaft.
Take the small finger of your right hand and place it in the gap between your forefinger and your middle finger. Enclose the rest of your hand around the shaft of the club and place your right thumb down the shaft, in the same manner your left thumb is placed.
For a majority of shots, you should grip the club at about a "5" on a scale of 1 to 10. That's the equivalent of a firm handshake with a new business associate. If you grip the club any looser, it will wobble on impact and the ball will almost certainly slice off to the right. Any tighter and it's unlikely you can have a full and relaxed swing.
Looking for the Vs
If you are holding the club correctly, you will notice an upside down letter "V" formed by both of your hands. The point of that "V" should be pointed somewhere in the neighborhood of your head and your right shoulder. This positioning should give you the assurance your hands are in a position to work together and give you an opportunity to put a consistent swing on the ball.