Peaches. Booty. Whatever you call them, the glutes are essential. There is really no exercise that lifts the glutes better than a Single Leg Romanian Deadlift (SL RDL). It is one of my favorite lower body exercises. You get a lot of bang for you buck with this one- core, hip, knee & ankle stability all the while working on your hip mobility. It is an advanced exercise, so try it first without weight and slowly start incorporating external load.
Here is a great video demo by Molly Galbraith of Girls Gone Strong:
