The guidelines for tee height are as follows:

Imagine a line around the center of the golf ball and the top half of the golf ball needs to be above the top edge of the driver. This would be the minimal, and depending on personal preference it could go higher. Pro shops have begun to sell the longer tees to keep up with the size of the new drivers.

This encourages a swing that swings up on the golf ball instead of trying to hit down on it.

Imagine yourself swinging uphill (see below) To hit the ball high imagine yourself swinging uphill. This visualization helps to keep you behind the ball when you swing out at the target. Too many people get out in front of the ball and lose the natural trajectory of the shot.