Sand the guitar with a medium-rough grit sanding sponge.

Follow the grain of the wood while sanding.

This is a hard and time consuming process. Expect to spend at least a few hours on this step.

The surface of your guitar should lose any glossy shine after you finish sanding.

A sanding sponge will be especially effective on the curved areas of the guitar-- like the back and sides of your instrument.

If you are starting from a light color and finishing to a dark color only a rough sanding is necessary.

If you are starting from a dark color and finishing to a light color a more complete sanding is necessary.

Use eye protection and a mask at all times while sanding.