In the past you would go to a junior tennis camp for a week and they would have one day dedicated to videotaping your game. It was great, but still a lot of trouble and not immediate gratification.
 
Now, while I am teaching, I just pull out my iPhone and start videotaping. Unreal, and in slow motion! Excellent quality, instant gratification, memorable, easy and quick, plus I can send it directly to my student for future reference.
 
So much easier to video a player's match or at least some points and let them see it later. It is better than telling a player what they did wrong as soon as they exit the court, at a time that they are not listening nor in the mood for a critique.
 
This immediate feedback has really advanced the game. Really, there is no excuse for having bad form, just a simple push of a button. If not in a structured environment, ask a friend to take a video of the shot or shots you need to work on. It will really help. Plus, you can go on the Internet and get slow motion video of the top pros hitting the ball correctly. Don't live "In the past."
 
Good luck on the courts!