Stand with one foot with the other in front of you slightly.
Squat down on one leg, bringing the other leg forwards as you lower down.
Get to a 90 degree bend then extend back up and repeat.
Knee bending inwards past big toe.
Rushing repetitions.
Lacking control.
Start by standing on one leg.
Bend your active leg and as you lower down, keep your other leg straight and out in front of you. Go as far as comfortable then drive through the heel to push back up to the start position. Your knee should bend in line with your foot and have your weight over the active heel. Repeat for the desired repetitions then switch legs.
Avoid having your knee cave inwards past your big toe.