- By regulary cleaning your snares. You should take a look underneath the snares (look between the fretboard and the snares) when you've played a pretty long session... there is this freaky 'fungus'like stuff hanging down from them. So I'd suggest you'd clean them like, after every long session. I use a little piece of rag, thin enough to fit between the snares and the fretboard and I go up and down (nut to bridge wise) I also gently clean the top of the snares.
-By not smashing your guitar on anything. When our practising at home and you came to the luminous idea to wear the strap in stead of sitting down, watch our where you are going :) I have a small room and I must have banged in to everything that stands there.
-Don't freak out on it. A guitar is still a delicate instrument which should be handled with care imho.
-Don't keep in in too cold/moist places either.
When you want to clean the body: DONT USE A HANKY ! I did and now it's full of light scratches :( Use a little piece of clean rag (like the things to clean your cd's with) and don't press it too hard !
-Make sure you have clean hands (don't rush off the diner table to play you're beauty, wash you're hands first ! filthy pig :), or when you've played for a long time and you've swet like a pig make sure your dry your fingers when you can before you play again. I personnaly don't like to play with sticky fingers and it makes your snares rust much quicker and it gets these filthy stains on your body when you grab your guitar...

Well it's all I can think of for the moment. I'm sure there's plenty more that I forgot.

P.S. I even talk to my guitar to make her play better and smoother :)