It’s important to first determine what kind of session it will be. A live jazz session is different than a pop session and is recorded differently. But to start with, I will be talking about rock or pop sessions.
1. Unless you’re rich, do not go to the recording studio until you are well-rehearsed and ready to play. The studio is not a place to get stuff together. It’s a place to document music ready to be recorded. If you’re very rich and you want to go in the studio with a bunch of new players that you’ve never played with before and just see what happens, by all means try it, but I don’t recommend that for getting anywhere close to a professional result. With the tech stuff available today you can get a clean recording in your living room just to show you if your music is on the right track, so to speak.
2. If you are doing a pop recording the 1st recording should be laying down the bottom of the music, the rhythm section. As it is being recorded it’s important to have the vocalist sing a scratch track vocal so the musicians can respond appropriately. It may be just an upright bass and maybe bass, drums and piano or whatever. But this is the foundation of what your song is going to be and without it anything that you put on top of it won’t work. The bottom must be solid in everyway; timing, tuning and groove. Now if you have a problem with one of the instruments, you can overdub even one note, if you need to, provided you have discrete tracks for each instrument.
3. Do not use friends who aren’t good musicians. Many groups sacrifice a professional outcome for friendship. It’s great to have friends and I wholly recommend it but just because someone is your friend it doesn’t mean they can play. If it’s okay to not sound good than by all means use players that can’t play well.
4. If a player has a performance problem that lasts more than ten minutes move on and come back. It’s very important to keep the spirit right in a session.
5. If a click (metronome sound in your headset) is necessary, okay. If it’s a jazz session, I recommend not using it. Most jazz music tends to accelerate. So to have it artificially held back can have a bad effect on the natural building of the music.
6. Make sure to plan double the time it took to rehearse the song correctly, in your studio session.