I was going to suggest doing gluteus medius exercises as well....but not in by saying that it is "deactivated" or "flat from sitting all day".
Colourdrop, the reason I suggest gluteus medius exercises is because that is the part of your glute that is highest up. Thus giving the look of a "lifted booty". This muscle functions by abducting your leg so any lateral abduction of your leg will get this muscle. You can also tie a elastic band into a loop, put around your ankles and then walk side stepping. (does that make sense?) Also you can do a side plank on your knees, straighten the top leg, lift the top leg up while keeping the hips off the ground. (again I hope that makes sense).
All of this is in conjunction with squats and lunges which use the gluteus maximus.
I'm also a very strong believer in spinning classes for giving a beautiful ass!!!