I used to try doing that with mixed results. If it's too close all you get is an out of phase sound or a chorus effect. If it's too far apart, it screws up the timing in a tight song.
If ya can afford it, another solution is using an amp simulator. (ie, AmpliTube etc..) There's tons of presets that will shift a boring mono guitar left & right and add some reverb and echo too if you want.
Another is a plug-in VST chorus effect or echo.

The best way is just record the same guitar part twice and pan them extreme left and right. (works great on acoustic). Then add some room reverb to both channels so it fills in the center a bit. If you 'print' the reverb to a separate channel. (or record the 'wet' mix to a new stereo channel), you can save CPU usage by using the fader to bring the reverb in as necessary on that channel without leaving the reverb switched on. You'll probably want to apply some compression to the dry channels so that it evens up the sound difference between the left & right dynamics.

Copying and dragging tracks slightly apart from either works great on vocal harmonies though. Record a 4 part harmony. Pan the whole thing over the whole spectrum, then copy & drag the 4 tracks slightly behind the originals and reverse the way you panned the originals.