Stand in front of a box, bench, medicine ball, or even a staircase. Put your right leg back and rest your toes on the object. If you're in front of a staircase, try to have your foot on the second step and not the first or third — being too high or too low could change the emphasis on your glutes.
Slowly bend your left knee until your hamstring is parallel to the floor. Make sure to engage your glutes throughout the movement. If you're doing it right, you'll feel it on every inch of the motion. You should also lower your pelvis and ensure that your left foot is far enough forward so it is just above your ankle.
Straighten out your bent left leg while returning to the original start position.
Complete your reps, then repeat with the opposite leg.