Cut off the high end and low end waste with a low-pass and high-pass EQ effect, respectively. For most guitars, this will mean cutting at around 8 kilohertz on the high end and near 70-80 hertz on the low end. These frequencies are not exact--they will change depending on the guitar tone and the nature of the song. Thus, sweep the EQ a bit to hear how each change in setting sounds.
Take a few decibels off of the low midrange area, around 300 hertz.
Remove some of the high end "fuzz" at around 6 kilohertz. This is the glassy part of a clean sound, or the squeaky, fizzy sound in distorted tones.
Adjust the midrange, 350-700 hertz, to taste. This is the part of most sounds that adjusts the character of the tone, and it also controls how well a sound mixes with other instruments in a recording. Be very free with this area; don't be afraid to make constant adjustments. In general, lowering this range will improve the blend of a guitar with a song. Conversely, adding power to the tone will increase clarity and the harmonic response.