I completely agree with Ben. I always seem to play better with pros than I do with hackers. I think it's the sense of competition brings out my best game. When I play with higher handicap golfers I tend to try shots I wouldn't normally try because I can afford to lose a couple strokes here and there. When playing low handicappers I tend to take the highest percentage shot presented to me.
A few things to remember: aim for the center of the greens, do not go hunting for pins. If you have a fade, play the left edge of the fairway so you have room to move left to right, do not aim for the center centre hoping for a straight shot. If between
clubs, always take a bigger club and swing easier rather than the lower club and swinging as hard as you can. On par 5's, always play to the 100 yard marker on your 2nd shot. Don't worry about trying to reach the green in 2 unless you are inside 200 yards after your tee shot. On the green, just try to get your first putt close. Follow Greg's advise above and TRUST the line you have selected. If you know in your mind that the line you have selected is correct, the only thing you have to worry about is weight. Walk off your longer putts (over 10 feet) so you know how many feet it is from the hole to your ball - this will give you a much better idea of how hard you need to hit the ball (remember to factor in uphill/downhill slopes). The most important tips - don't let anyone else's game or actions get in your head. Don't let the last bad shot get to you. It's already been hit. Think about how good your next shot will be, not how bad the last one was. Lastly, HAVE FUN! People always play better when they are relaxed with a smile on their face. Now go out there and kick some butt!!