There are several ways to make guitar tracks sound good in a recording. One important tool is the graphic EQ. With a graphic EQ, you can adjust specific frequency points to affect the sound of the guitar in a recording. You can raise the upper mid-range frequencies around 1,000 Hertz to give the guitar that extra bite so that it will stand out in the mix without raising its volume. You can try lowering the 3,000 Hertz frequency while boosting 1,000 Hertz; this will reduce the glassiness of the sound.
Since the guitar has a lot of inherent mid-range and high-end, you can use a parametric equalizer to cut all of the frequencies below 80 Hertz, as they are unnecessary and difficult to reproduce with a guitar cabinet. By cutting these frequencies, the sound of bass instruments (such as the bass guitar and kick drum) will be clearer and easier to hear in the mix.
Another option is to increase just the mid-range frequencies between 400 Hertz and 800 Hertz on the guitar to allow it to sound fuller. Since the guitar "lives" in the mid-range frequencies, a slight adjustment may be all you need to help the guitar sound present.
Guitar EQ after recording should be used with care, as it can add noise to the track. It is best to have tracks that sound good raw, rather than attempting to fix guitar sounds after they have been recorded. Minimal EQ on a guitar track is fine, as subtle increments can change the sound of the track dramatically.