Entering an electric guitar store or a bass guitar store can be a heady experience for the uninitiated. There are generally rows and rows of shiny new and used guitars hanging from the walls. If the shop also sells sound equipment, there will most likely be a wide variety of amplifiers sitting on the ground, many of which will be hooked up so customers can try them out.Much of the guitar buying experience depends on personal preference. There are scores of professional musicians who will argue to death about the merits of one guitar brand over another, but the truth is that it basically comes down to which one you like better. Some brands are known for producing a particular "color" of sound, but by and large a guitar's "sound" is determined by the player.
The good thing about quality guitar shops is that you can actually get the chance to try out the various guitars before you make a decision. They will generally let you just plug into an amp and play around to see if you like the way the guitar "plays." If you are a novice, this can be a bit overwhelming, but as you get better and better, your personal playing preferences will become better defined and you will be able to quickly eliminate guitars and easily determine which ones feel "right."
Going to a used guitar shop or a vintage guitar shop can be a great way to find a used or "classic" guitar as well. It's great because you can actually get a chance to try the guitar out before you pay for it. Guitars, like everything else, age, and sometimes the electronics don't hold up as well as they should. It's a good idea to play used guitars on a couple of different amps to see how they sound. You should also remember to switch between the pickups to ensure that they all work.