A few photographing tips

:: Place your guitar in front of a quiet and contrasting background.

:: Don't waste pixels. Get close or use the zoom. If you feel you're close enough get a little closer.

:: Use a tripod if you have one.

:: Avoid using the built-in camera flash if possible! The result is unpredictable, you get lifeless colors, shiny spots and drop shadows. If your camera doesn't allow to switch the flash off tape it off.

:: Daylight is the best light you can have. Picture your guitar outside or beneath a large window. Avoid direct sunlight because it also drops shadows. Wait till the sun is hidden behind clouds. It's always good to aim some extra light towards the guitar by putting a large white surface (e.g. cardboard) in front or to the side of it.

:: Read these great pages on photographing your guitar:
BunnyBass phototips: suggestions & ideas
Niels Gerhardts Foto-Workshop - Wie Instrumente ansehnlich fotografieren?
If you have an external flash that can be tilted straight up towards the ceiling learn how to make a better bounce card for mixing indirect and direct lighting.