doubling with duplicate track

[take77]

Definitely on the same page as albee1952. All good and practical advice from everyone.

Tracking a second live performance by actually playing along with the first one creates a natural chorusing effect that sounds suhhhWEET.
When the double tracking is tight (yet human) and things are smooth & in phase, it adds a natural harmonic enhancement that no amount of editing can add.

I also understand that sometimes it's late and your just working with the tracks available inside PT.

If possible, use a different sounding but complementary guitar for the second track. Or a slightly different tone.
You can also create a rich sound by using MEDIUM gain* for each track.
The two tracks will combine to create a richer, more dynamic level of gain; with more clarity & girth.

*When recording with distorted guitar tones

If double tracking a clean & arpeggiated (broken chord) part, try this:

Using the same guitar, record one track in neck position & the other track in bridge position.
This combines the fullness & warmth of the neck position with the articulation and clarity of the bridge position.

Just some extra tips on combining two tones that are different yet compliment each other in a musical way.