Re: Breaking 90?for me it was realizing how many shots I threw away by topping balls and such. once i stopped doing that I shot in the 80's easily. Also if you dont top any balls, dont take many if any penalty strokes, and avoid 3 putting, breaking 90 is nothing. Hit your tee ball, if you can hit the green, if you cant punch out and then hit the green and take your chances with yoru par putt and at worst make bogey. If you missa green, make sure the next one gets on the green, no chilli dipping or flubbing shots around the green, you should never do that really unless you are trying to get cute with a very difficult shot. Just keep advancing the ball positively and no shanks/tops and youll be well on your way to mid/low 80's
edit: I saw someone else post an idea I forgot.
ALWAYS take more club on full shots and hit the ball almost always a little farther than you think you need to on your pitch shots/chips, Most high handicaps rarely flush the ball so the odds of you going long are pretty small, and your odds of hitting the green on a mishit go up dramatically with a longer club. Pace off yardages and stuff too, get exact numbers in your head dont just eyeball, it will help you out greatly in the long run. I honestly never see high handicaps hit the ball long, they are almost always painfully short and having to chip/pitch again and it ruins their scores. MAKE SURE you hit it hard enough to get it on the green. Also, for the love of god accelerate through your chips/pitch shots, take a shorter swing and swing briskly, like gary player said on his tips from the pros, you want to think of it like lighting a match, you need to have some acceleration through the shot.