Something I do in Reaper when I want to redo a part is to set my record for Punch-In. That way I'm in the groove so to speak with the song and recording starts when I get to my preset selection. If you zoom out on the waveform you can get your punch in and punch out points set properly. Other DAWs have this ability as well I imagine.
On the collab, I just start normal record from the start and start playing at the right time using the rhythm of the song for my timing. If I make noise on my track at the point I wasn't supposed to be playing like before my spot, I can go back and silence the before and after. Then I just mix the two tracks together.
I also usually run through a track several times so I get familiar with the track as far as where the breaks are, etc.
