Osoto-Gari's key points:
1. 3-step movement to bring your attacking leg closer to uke's target leg
2. Sleeve hand pushes towards the back; Lapel hand gets a high grip
3. Both hands steer uke towards the direction of the throw

Kosoto-Gari/Gake's key points:
1. Attack the near leg
2. Aim for the heel, not the ankle (ankle is for ashi-barai)
3. For kosoto-gari, your knee points to the front; for kosoto-gake, your knee points towards the back
4. In modern kosoto-gake, the point of contact is not your foot to uke's heel but your calf to uke's calf. It also involves a bear hug.