I've got a couple of weeks of from school atm and would like to use that time to practice as much as possible. Because most of my tennis buds don't have as much free time as I do, I'd like to fill some time hitting against the wall. Instead of hitting some braindead balls, I'd like to do some drills that actually improve my game. I searched around a bit, but only found a couple of useful drills. One of them is hitting a crosscourt shot (to either fh or bh), hit a down the line shot and go crosscourt to the other shot again and repeat that until I fail. Another one is serving against the wall (which I've never done) to work on service returns. I'm pretty sure that must be some more good drills that I'm not aware of though and if you guys happen to know any I'd be happy to hear them. Thanks!