Ed and I are currently taking tennis lessons through the City of Lakewood. Our class has been really small - the highest number of people was four, and that was on the first night; since then there have only been three of us.
Last Wednesday, Ed worked late, and I was the only one at class. So I basically got a private lesson for 50 minutes, which was awesome and also exhausting.
The tennis teacher kind of takes an iterative approach to improving us, which I really appreciate. As an example, this is how he improved my serve.
First, he had me do a few serves. Most of them went in, which is generally about the best thing you can say about my serve - it does go in. I stand sideways to the court (like you're supposed to) and start with my racquet over my shoulder and sideways to my back - like I'm scratching my back with it. (This eliminates having to do the back swing - you just come forward with the racket instead.) Then I toss the ball up and hit it (duh).
After he watched me serve 5 or 6 balls, he said, "Now I want you to toss the ball higher." So I tried that, and he kept pushing me on it, for perhaps 10 more serves.
"OK," he said. "Now I want you to follow through with the racquet to under your left arm." He demonstrated, and I tried to replicate the motion a few times without actually serving. Then I served balls that way, at first not getting them in (and thwacking myself once), but then learning to get them in with this new style. I did notice, once they started going in, that they were indeed better serves.
So after maybe 15 of these serves, he said, "All right. Now I want you to lean into the court when you do it."
I added that to my serve, hit about 10 more balls, and we were done with serving. I think my serve got much better over just this ~ 10 minutes (if that) of instruction, and without my having to be overwhelmed by 20 different new ideas all at once.
(In the picture above, you will note that Goofy has mastered a skill I have not - stepping with the correct foot for a volley.)