Calf raises are key, I usually try to do them slow and go low and also do more than 20, I do both seated and standing.

As for upper legs. Leg extension and Leg curls are good after exhausting with Squats. I also used to do drop sets on the seat leg press, maching looks like this. Would have a guy on each side, start at 5 plates and do ten reps, get them to take a plate off after ten and go till I did no plates ten times. I will warn you this workout is killer and I have come close to puking a few times, mid workout protein shake is key for keeping your energy up (at least for me it was)