There are different reasons for people to take martial arts classes. The two main reasons are usually:
- workout : all about the burn
- protection: all about defense
Class should be carefully structured so that there is a good warm-up with cardio (followed by some light stretching) so the instruction that follows can be done with "warm" bodies. Circuit training is ideal for warm-ups, and if you use the right kind of moves, you can also incorporate some practical instruction (cross punches, kicks, squats, are all good for learning attack and evasion moves).
Take these two workouts:
I use both of these for the "calisthenics" portion of the class. The Ronin workout is particularly effective on the days we are doing escrima stick fighting. The Batgirl workout is awesome for warmups on days we're going to be doing sparring. (incidentally, if you like these, I highly suggest Neila Rey's circuit workout series)
Some days I'll instead go with yoga or maybe a Pilates workout, because we're going to be doing some serious kicking or punching. The teens seem to hate these the most, but I'm a big believer in keeping flexible. But it's good to mix things up so that you're targeting the areas you may not be working as hard, or to stretch out areas you have been working out instead.
Most importantly, make sure that when you are instructing you avoid using what could be considered inflammatory language or call out individual students. The exception to this would be if you notice someone that is doing a exercise incorrectly and it may injure them. Then you need to call them out or they will get hurt. Make sure to offer variations for the exercises when you can (if you have back issues, do kneeling plank; if you have shoulder issues, don't raise your arms above your head) to keep your students safe. And always listen to feedback. There may be complaining that is just whining (I hate planks), and then there's complaining that needs to be addressed (lunges make my knees hurt).
Keeping it fresh will keep your students entertained, and their bodies won't get too used to a particular workout. Have some fun, and keep them safe.