What do you have to look for when buying an acoustic guitar?

Always play before you buy (if you can't play ask the shop assistant to demonstrate), if it sounds good check the sturdiness of the neck and test for comfort of play (some lesser branded guitars have unusually large shaped bodies and too wide/narrow necks), but most importantly - only buy the guitar that feels like your guitar the moment you pick it up.

Not only should you play before you buy, you should play it, leave the store and come back another time to play it again. Weather conditions change the acoustics of the guitar so you want to get a range of tones from the guitar. If it sounds like crap, you won't like playing it. Get something that feels really comfortable in your hands when you strum it. Most acoustics have very thick sticky lacquer on their necks so make sure that you can slide up and down the neck a bit.

Look based on the overall sound that you want -- if you want a big, deep sound you're going to need a larger than average body.

Also, look based on what you need for the next year or so. If you're a beginner and you're not sure if you're going to stick with it, don't spend a lot of money. Look at the Martins, although these can be pretty pricey. My personal favorite is a Taylor, which retails for around $3500 in the US.

I've been playing for about 30 years although mostly electric, but I do play the acoustic from time to time to strengthen my fingers.

it depends on you,if you have a small hand you would like a narrow necked guitar. if you have large hands (like me) any guitar will work.i have 3 acoustic guitar's and i like them all.i even play a 12 string which i really like.quallity is always the best place to start. depending on your budget.there a some mighty fine knock-offs but always ask about the guitar.(who made it,where it was made).do a little research.i find that (guild)makes a really fine guitar but if you need something a little less pricey try a copy.