Watching a video of yourself playing tennis can be a revealing--and entertaining--experience. Following are various techniques you can use to get the best video footage of your tennis strokes and tactics.
The most fun video to watch is match play. You'll probably notice all kinds of things you didn't realize you were doing, and you're more likely to do things you're unaware of in the heat of competition than you would be if just filming an isolated stroke. Among the more common examples are looking up at your opponent before striking the ball, not hitting sufficiently crosscourt on defensive baseline-to-baseline shots, and backing up while swinging.
The best way to film a match is to place the camera on a tripod around five feet high and as far behind one end of the court as your camera's zoom will allow. Placing the camera far from the court allows you to capture the entire court and greatly reduces the apparent difference in size between the two players. You'll have to shoot through the fence, but as long as there's no windscreen, the camera will capture the tennis quite well.
Zoom in so that the width of the camera's field of view extends as wide as you tend to run to get a ball; for a quick singles player, four feet beyond the doubles sidelines should do for all but perhaps a few extreme shots. A good bottom for the camera's view is the bottom of the near fence; that should leave plenty of room to see the full flight of lobs.
Most tennis courts are oriented so that the ends are on the north and south, thus saving the players from looking straight into the sun in the early morning or late afternoon. Your camera won't like looking into the sun either, even if the sun is just hitting the lens at an angle, so place the camera so that the sun is slightly behind it; outside the tropics, the sun is always somewhat to the south or north.
If you want to capture close-up video of individual strokes, bring the camera onto the court and have someone feed you balls; the camera is too likely to get hit during match play. For groundstrokes, the camera's best view is usually directly from the side you'll be facing. For serves, a side view can be useful, but a view from directly behind is usually most informative, and make sure to zoom out enough to see the full flight of the ball toss. On all strokes, leave enough room at the bottom of the camera's view to capture what your feet are doing.