Your personal health is honestly the biggest key in a great photo session. Get plenty of rest the night before–preferably a full night’s sleep. If possible, you should try to get 7 to 8 hours of sleep not only that night, but EVERY NIGHT for at least a week before the session.
Puffy eyes from lack of sleep can be corrected with ice packs before makeup application, and can be further hidden by a great makeup artist and photo editing team–but do you really want to have puffy red eyes in the even your team doesn’t have at least one of each who are extremely gifted?
Also, tired eyes look dull, glassy, and a bit dead in print. There’s no vibrancy and life, and if you are tired, it tends to show in how you hold yourself and right down to a slight limp look in your features.
Do yourself a favor. Get plenty of rest. I can’t count the number of shoots when I first began that would look ten times better if I had not been so stressed and exhausted.