Micro games, you gotta play premium only hands, and punish the KT-playing donkeys.
The biggest difference between MTTs and micros might be the bluffing, as was said above, but if you're talking normal rings, then the biggest difference is this:
basically in MTTs, you're supposed to only be all in if you're a massive favourite - like 82% ( PP vs. smaller PP )
with rings, any tiny edge will profit in the end, so theoretically you should play any advantage over %50 (though i would probably never call an all in with 22 type hand....
The thing is you have to have your hand reading skills honed to perfection - you have to be %100 sure that your opponent has 2 overcards in order to call an all in with a pocket pair.
but basically my strategy with all ins in ring games is calling only with AA or KK for an all in, unless my opponent is a maniac or a shortstack and i know he is trying to steal.
Bluffing at micros is next to impossible, but if you're talking .25/.5 and up, it's a key tool to use at ring games.