Bogey Pro,

 Great question.  It is one of those "what to dos" without explaining the "how to do's" we read or hear so let's explain it now.

Excessive grip pressure at the beginning of your swing can be and usually is a killer.  Understand as your swing starts and progresses to the top and through impact you naturally increase pressure to control the weight of the club. If you start with too much pressure you cannot have the natural increase in pressure that occurs (see Golf My Way by Jack Nicklaus) and the opposite actually occurs and you lose tension and get that "all over the place" feeling. Let's change "grip pressure" to "tension" and tension, since the first book on golf instruction was written, is the killer of the golf swing. 

Believe it or not, grip tension is caused by incorrect posture.  The effects are an unconventional grip, too much pressure and the arms in a tense and too angled a position.But there is a simple and easy correction to get to the proper grip formation and proper tension.  Here's the simple way to find it:

First stand in front of a mirror in your normal posture.  Now look at your hands.  Are your palms facing behind you or hanging to your sides with your palms facing inwards towards the side of your thighs?  If they are facing behind you then when you go to put your hands on the club (your grip) then you automatically create tension in your hands, forearms and elbows.  To correct that, use this simple cure.  When you are standing in front of that mirror and see your hands looking backwards (most recreational golfers do, by the way)  scrunch your shoulders towards your ears then push your shoulder blades back and down your back.  Turn to one side and see that now your earhole should be directly over your the points on the tops of your shoulder and that line should run down through your hips, knees and shoulders.  You should also see at that point your palms facing the sides of your thighs.  From there you can begin to get into the correct posture by keeping your shoulder blades back and your earhole in the same line and bending over from your lower hip joints until you almost fall over on your heels.  Then let your knees bend slightly so you feel centered over your feet with about 60% of your weight towards your heels and 40% towards your toes.  Your arms then will be hanging directly down over your shoes and the plams of your hands facing each other.  Once you are there, then you can apply your hands to the club with minimal tension because you will have almost no tension in your arms at address without the club. 

Now that you are there, apply the hands so that on a scale of 1 to 10 (with one barely keeping the club off the ground and 10 being where you might break it in half or choke a snake) with a pressure of 3 or 4.  Now when you begin swinging you will gradually increase pressure naturally and be at the proper pressure at impact.  You will sense lightness in the grip pressure and firmness in the wrists at impact.

Check yourself in the mirror, make the adjustments there and then remeber them so you can take it to the practice range and the course.

Good luck and let me know how you do.