Playing the part twice is the best way. After that, there are lots of options(but they are not likely to work as well). Some to try:
1-duplicate the mono track(hard-pan the original and duplicate opposite of each other) and experiment with ways of changing the duplicate(you need to give it enough change so its not going to sound phasey). Options there include changing the pitch slightly(Elastic Pitch and push the audio lower or higher by anywhere from 6 cents to 11 cents, or use Waves SoundShifter. Or insert AutoTune, set for instrument and adjusted several cents up or down).
2-put a mono send on the guitar track and feed a MONO AUX track and insert a mono reverb(Dverb works well for this). Pan the original hard to one side and the AUX track hard to the other side(and make sure the reverb plugin is set to 100% wet).
3-when all else fails, hit youtube for some tutorial videos.
