It's important to go to a shop that only sells acoustic guitars.
When I bought an acoustic i tried many of them in a special room. I had all the time. All the guitars i could easely try from cheap to very expensive ones. When I made my choice i waited a while and went back another day with another guitarplayer and let him play it to. It's good to hear someone else playing on the guitar. The difference in sound is great. Take the time to find out what you really like.