General:
* Rehearse, rehearse, rehearse!! Pick your song(s) apart. Know EXACTLY what EACH part is going to play at EVERY moment of the song. Precious time is often wasted when the guitar player has to figure out how the solo is going to go, or finding out that the drum fill is not going to work with the instrumental re-entry and needs to be worked out better. Some things can work live if they are a little sloppy, but recording will expose these weak areas, and they will stick out like sore thumbs.
* Get a good night's sleep, and be well-nourished. Mistakes happen when you are tired. Physical energy often translates to performance energy.
* Record with a clear head. You might think you play better with a few beers (or whatever), but typically, you don't. Various substances just make you more forgiving of sloppy playing, bad tuning, and loose timing.
* Make decisions, commit to them, and be prepared to communicate them. While recording, you shouldn't be bickering about how to end the song, or whether or not the bridge is working. Write out the lyrics with notes about the arrangement on a sheet of paper, or use your cellphone to make a rough recording at rehearsal. Best yet, do both!!
* Overall, remember that time is money. The faster you can get things done, the less your recording will cost!
* Do NOT bring along friends, girlfriends, boyfriends, spouses, neighbours, financial advisors, hairstylists, etc. I know everyone means well, but my experience is that it hinders the process on a few levels: