The Caruso technique is a series of exercises designed by Carmine Caruso to strengthen your embouchure, give you more endurance and help your whole register. It also helps focussing your tone. I never had lessons with Caruso myself but I had the chance to study with one of his students for a couple of years so I learn it from someone who got it from the master himself. Good enough!
A few golden rules about this technique:
1) Do it only once a day. You might hurt yourself if you over do it.
2)Do it 3-4 times per week. You can do it more often once you're strong enough but never more than 5-6 times per week.
3)Don't force the notes out. Be patient. With time, you'll become stronger. You should see some effect on your chops in 3 to 4 weeks.
4) Don't follow it blindly. Adjust the frequency and number of exercises you do to your own needs. Experiment with it and see what works best for you.
You can find the basic Caruso on this website:
"The Basic Caruso"
Here is another site dedicated to Carmine Caruso.
Carmine Caruso Tribute
I am associate principal horn of the Singapore Symphony Orchestra and the author of the progressive methods. I'm happy to share my experience as a horn player and teacher with you.