Begin standing on one leg and slowly reach both hands forward and down toward the cone. Allow the free leg to move behind you and keep the stance heel on the ground. Lightly touch the cone at the bottom and return to the full upright position each time. Perform 10 repetitions and repeat on the other side. Repeat for 2-3 sets.
Be sure to keep the knee tracking over the second toe. I often cue clients to imagine a laser beam pointing out from the center of the kneecap and over the second toe as a cue. Discourage any excessive valgus or hip internal rotation/adduction during the movement, and watch for overpronation as well.
The exercises can be done in front of a mirror to offer visual feedback. Additionally, I will place my hand medial to the stance leg and tell the client not to let the inside of his/her knee touch my hand on the way down to offer kinesthetic feedback as well.