Is the Grip Really That Important? How About Interlock?
Let's think about this. The grip is actually the only connection you have to the golf club face. The big difference in this game is that the golf club is further away from you. Moe Norman used to grip all his clubs at almost the same length. He would choke up on his longer clubs. I think it was the Tommy Armour company that tried to mimic Moe and built a set that was similar to how he held a golf club.
Another huge feature is that a golf club has the axis or shaft, on the bottom of the head. A tennis racket has the axis balanced in the center. This causes you to have to place extra effort to roll the golf club over through the impact area. The same way a tennis player puts top spin on a tennis ball.
If your left hand grip, (for right handers) is not STRONG enough, you will have trouble playing this game. What is considered in golf books as too strong a grip, television commentators on golf tournaments refer to as a "players grip." Well, if most of the golfers on tour are using a strong grip there must be a reason.
Below I posted a video for you showing where the grip should be. Bottom line is, if you hold the golf club in front of you and grip it with your left hand, you should feel as though you have enough of your left hand on the right side of the shaft in order to have "leverage" to rotate the golf club counter clockwise. I like to think of the top of the shaft as 12 o'clock. Your left thumb should be at least at 2 o'clock on the shaft.
Take a look at this video and let me know if it helps.