I am working to transition from being a counterpunching 3.0/3.5 singles player to a solid 4.0 doubles and singles player. I just got bumped to 4.0, and I am finding that I have to add more penetration and placement to my groundstrokes and more attack in general to survive at this level. In doubles, I sometimes struggle with keeping the ball away from the net player. I will hit two or three good, deep "keep away" shots and then end up looping one a bit short and BAM they put it away. Are there some good drills to practice with two people that penalize you for hitting a poachable ball? I have been practicing rallying crosscourt with one other person, which is great for singles and I'm sure for doubles, but sometimes I think it still lets me be a bit lazy about keeping the ball away from a net player. I don't get that emphatic "you messed up" when I leave a ball short or in the middle too much. Any advice? I would like to find something I can do when just hitting with one other person.