It's important to keep your guitar clean to make sure it sounds as good as possible and that it lasts as long as possible. Every time you finish playing you should wipe down the strings and all the surfaces. Cleaning the strings will improve their life span.

Make sure you wipe the surfaces (body, neck) of the guitar with a non-abrasive cloth. A soft cotton cloth works best. You can use any spray cleaner that is designed for guitar surfaces. But in my experience a dry cloth works best. If you have to get gunk off, then a damp cloth first, then a dry one to follow!