I turn auto-crossfades on (on all tracks, but can be set for each track). That means I usually don’t have to manually crossfade or use zero crossings (which I personally don’t like…).
Also useful to use the Alt-drag method on the audio event. This slides the audio within the event. Sometimes quicker if you cut in the correct place (e.g. on the beat) and then slide the audio, but it depends on what happens at the other end of the cut, may not be quicker…
Quite often when I’m recording things I’ll ask the musician for a special take which has less in it, e.g. less riffing, less strumming (particularly ends of sections for sustained held chords). This track I can then use in the comp to replace short notes which are just out of time & too short to stretch or put back into time without creating a problem noise. I would probably do this if I see that the musician is having particular trouble with a passage and I’m getting a bit edgy about how long it’ll take to fix up afterwards 
Mike.