Upon completing the body of your guitar, you may decide that you want to sand it, either to get out some dent or another from the guitar surface, or to round off the edges of the wood so you are less likely to get a splinter from the wood. There are many different ways to sand wood effectively; I will cover a few of the simpler of these ways here.
The simplest way to sand wood is to get a piece of sandpaper and rub it back and forth across the section of wood that you are trying to sand, pushing down on the sand paper for added effectiveness. Eventually, you will wear away as much wood as you need. If this is taking too much time, you can get an electric sander. To use a vibrating sander, the simplest model to use and the model that we used in class, simply clip a piece of sand paper tightly into place on the sander's vibrating pad, switch the device on, and move it back and forth across the area that you want to wear down, exerting a slight downward force on the sander.
If you are trying to sand in a sharp corner, or if you are trying to wear away a groove, it is probably best to use a Dremel tool with a sanding attachment. Simply figure out which attachment best fits your purpose, put it in the tool and turn the tool on, and start sanding. Beware, though, that the sanding bit will tend to wander; it is a round object that is spinning, so it will tend to act like a wheel and push the Dremel and the guitar body in opposite directions. I have found that running the Dremel at higher speeds seems to lessen this effect.
Just for some more fun, I'll go into the different types of sandpaper. Sandpaper comes in an array of different levels of coarseness or fineness. Finer sandpaper will create a smoother sanded surface; coarser sandpaper will wear away wood faster. It's pretty easy to tell if a given piece of sandpaper is coarse or fine just by looking at it, or even feeling it; coarser sandpaper is, well, coarser, with bigger granules of hard stuff glued on its sanding surface. For the purposes of this guitar, a medium sandpaper will probably work just fine; for an extra level of quality, you could start off with a coarse piece and finish off with a fine piece.