Stand facing either right or left while planting all of your weight on the foot closest to the mirror. Focus on really pushing hip towards the mirror.
While keeping all of your weight shifted to the leg closest to the mirror. Take a backward step with the opposite foot. Place your non-selfie hand on the front of your thigh on the planted leg. Don't forget to keep your tummy tight (throw in a tricep flex). Smile. Snap.
Stand facing away from the mirror in a 45 degree angle. You'll need to shift all your weight to the foot closest to the mirror.
"Sit" into the hip facing the mirror (basically popping your hip to point your booty straight at the mirror) and bend the knee of the opposite leg. Place your non-selfie hand on the front of your thigh of the planted leg. Don't forget to arch your back and keep your tummy tight. Smile. Snap