I find the trick with short putts is to hit them hard enough to eliminate the break, at least a foot too hard. If you get it wrong on tourney greens you may find yourself with a longer return putt than the one you just had but anything is better than seeing the ball wander by the hole or stop 2 inches short.
Chipping has more than it's share of problems, there's an excellent guide here though: http://www.wgt.com/forums/t/7840