Getting ready together can be a blast. These hours of primping promise rich conversation (from silly to serious), sips of champagne and precious photos that preserve the final moments before the bride walks down the aisle to a new life with her partner. She probably will need help getting into her gown (or into a bathroom stall). This is a staple bridesmaid duty.
So is the responsibility of makeup. You may do her makeup for her and for yourself. Or both of you may be in professional hands. Either way, you're in charge of having her put her best face forward on the big day. The bride's nerves may be raw, so this is the ideal time for you to be encouraging, reassuring and steady-tempered.