First & Foremost... Be Prepared, Know Your Material
Spending studio time rehearsing a tune is a waste of time and money and can bleed energy from the performance. If you anticipate doing overdubs, take the time to figure out the parts before the session. "Feeling it out" while tracking can be effective but takes time.
If
you are a vocalist, it's best if you know your lyrics by heart. Reading as
you perform distracts you from your performance and tends to pull you off
mic-axis.
Do what it is that you do to warm up your vocals before recording, singing
scales and arpeggios, for example. This helps to loosen up your vocal chords
and improves pitch accuracy and tone.
Guitarist should have new strings on their instruments, but preferably a day
or two old with a bit of playing in since brand new strings need to stretch
to avoid tuning hassles and also sound ultra bright and "brittle"
(Just my opinion). Have a set of spares. Also, check intonation to (once again)
avoid tuning issues.
Drummers should also have reasonably new vellums. Check that no loose "bits"
are causing rattles, etc. as microphones are extremely sensitive. The live
environment can be really forgiving and much can slip through the cracks whereas
the studio brings weaknesses into sharp focus.
It's
a good idea to discuss your plan and vision with the studio engineer so that
all parties can be well prepared for the day's ahead.
Be prepared for a bit of set up time. Check out what you can do to use your
time constructively while other band members are busy. e.g. a vocalist can
warm up his/her voice while the bassist is doing some overdubs, or a guitarist
can change that broken string and work it in while the vocalists is tracking
a lead vocal.