All of the above...
...some pretty good advice here. If there's any consistent theme, it's "here's what you could think about doing to improve at your current level" versus "here's what the game of doubles is really all about." In men's doubles at the 4.5 level and above, there's some givens:
- Serve and volley on both serves.
- Chip and charge whenever possible. Keep the return down, make the server stretch for the volley, try to get up to net with your partner ASAP. One up/one back is a clear invitation to the other team...want a point? Just hit through the diagonal! On the other hand, if the other team knows anything about volleying and can get to the net together, assuming you and you partner elect to stay together...but on the baseline....you just lost the match. The score might be 6-4, 7-6 or 6-2, 6-3, or whatever, but you just gave away the crown jewels.
- Court positioning/strategy is not necessarily what everybody thinks, and some of this came out in the preceding comments. As one of my coaches said, "In doubles, each person has a job", to whit:
- Server. Serving from way out near the singles lines is not really a good idea. You've just telegraphed that you're going wide on your serves...and if you're not, the serve in the duece court down the T is going to be a hazard, because it'll break into your opponent rather than tailing away. If you're serving from way out, you've also just left your partner with two unenviable choices: (1) Move over to cover the hole down the middle, and give up way too much space down the line, or (2) leave the hole down the middle open...and you can mail in the results of the match, see above. Serving from a little wider than your normal service position for doubles is fine...but if you can't hit a variety of serve directions/spins from there, go work on your serve, don't go stand way out somewhere.
If you're not going to serve and volley, serve, hit the first groundstroke, and move in. If you put it off any longer than that, you're partner is stranded, the other team just took over the net, and you just lost. Obviously, a good forcing serve is essential...but as others have noted, you'd better get in at least 70% of your first serves, or...you lose.
- Server's partner. Most important player on the court. On every point, the server's partner, who is at the net, should either be faking or poaching. This means you gotta communicate with your partner, either via a strategy discussion before the point or via signals. You make the "poach or not?" decision as a team before the point, so neither one of you gets surprised. So what if your partner has a 57 m.p.h helium ball for a serve? Well, you do a lot of faking, and resolve to work on the serve next week in practice. You're also governed by what your opponents do, however. If the other team returns a 57 m.p.h helium ball to the same spot every time...well, I'd think about poaching. As somebody said above, stand maybe a racket and half's length from the net, in the middle of the service box. Yeah, you'll give up a little of the line...but the middle of the service box is just your starting point. You're allowed to move, once the point starts, if you see the returner winding up for a bullet down the line. And you're never gonna be able to poach effectively if you stand over on the singles sideline.
- Returner. Okay, I'll say it again: A doubles return is different than a singles return. Doubles is a different game than singles. All I ever play, any more, is singles, so if I wind up playing doubles, I know it's going to take me at least a set or two to get the movement, strokes, strategy and rhythm back on track.
In ATP tennis, most of the guys play Andy Roddick Smashball, where you hammer a serve, the returner tries to hit heavy crosscourt through the court, and then we settle down for some heavy-duty long range artillery with 100 m. p. h. backhands and forehands. There is a trickle down effect all the way to most public parks/NTRP/high school tennis: everybody bangs the big serve, the returner goes for a heavy topspin return, and you're off the the races. In doubles, get lots of returns back (there are two guys on the other side of the net, and they're supposed to win their serves), make the other team move and stretch, and keep the ball down. I love people who belt a return off my serve that ends up going a 100 m. p. h. three feet over the net. Response: angled volley at the net man's right hip, point over.
When you get a break in doubles, it's rarely at love. Usually, you get to 30-30, and scratch together a couple of winning points to get the break. Therefore, assuming you're both righties, who has the better backhand return in the ad court? Because at 30-40 or 40-30, you need to get the return back so you can break...and in high school tennis, the chances are you're going to see a wide serve out to the backhand. It's also a reason why if one of you has a streakier return, put that person in the duece court. If you get a winning return in the deuce court, Mr. Steady in the ad court can then finish off the job. The reverse strategy doesn't work as well.
- Returner's partner. The guy in the Danger Zone. If your partner hits a duck return, guess who's going to see the ball next? Answer: you, and the ball's going to be trying to dig you another navel. Returner's partner starts off on the service line, halfway between the center line and the singles sideline...and you're facing the server's partner...because if there's any trouble, that's where it's going to come initially. After the point gets started, follow the ball, and stay with your partner...