I'm not a tennis coach and I've never played tennis, but I know what is the most thrilling part of tennis, I've been watching every game in the big tournaments for the last 10 years, people love to see:
No one can always deliver a good rally as you already know, and you know all about aces :D volleys and smashes are rare but I think the best way to thrill the fans and to win a game is to have a great footwork and stamina, because all the professional players have good shots, besides you can't rely on good serves to win a game, it's not always your serve. Some players have bad forehand or backhand and still win, because they have great footwork speed and stamina, if you have a good footwork and speed you will be able to win all, Federer is the best why? because he has great footwork and speed, stamina is so important as well because tennis games are so long. The match Federer vs Nadal (Wimbledon final 2008) is the greatest ever and why? because both players had an incredible stamina and footwork and that's what we want to see. That's the thrill. I'm not saying that having a great serve, backhand and forehand isn't good, I'm just saying that the stamina and the footwork are the most important factors.
Then there is the attitude of the player on the pitch, nadal is one of the most loved players in tennis, why is that? because he give you a thrill every time he's on the pitch, sometimes he's bad sometimes he's good but the fans love him no matter what because of his attitude.
The show : giving the fans a good show is a great thing, we loved Sampras and Agassi because they deliver the show, they smash the ball a lot, go to the net....And that what people want to see.
Having fun :John McEnroe says it all :D and people love that.
So whether you deliver a good game, a good attitude, a good show, or simply being funny you'll give us the thrill of watching you - AND THAT"S TENNIS right?