Update from yesterday (in case anyone cares):
I ran a forehand drill similar to one in video Relinquis posted. Basically, I had them hit two angled crosscourt forehands, followed by a down the line forehand. I explained the first two shots were designed to pull the opponent outside the doubles alley and open up the court for an easier down the line shot. Two of them got the hang of it quickly, the third coming around near the end.
However, after practice my #1 player asked if I could stay & hit for an extra 10-15 minutes. We started just hitting balls, but without me saying anything, I set her up to hit the pattern. Not only did she run the pattern, but she took it one step further by stepping in on my reply to her down the line shot & hitting behind me as I recovered.
I stopped and looked at her, and she had this huge smile on her face. She knew she had run the pattern, but more important, she saw its effectiveness in an actual hitting situation.
"Nobody beats Vitas Gerulaitis 17 times in a row" -- Vitas Gerulaitis, after beating Jimmy Connors on his 17th try.