Let's see what EF Goldman had to say about his book “Daily Embouchure Studies”. You can have a look at some sample pages to the left and grab a PDF download above. From the author:
“These exercises were written twenty five years ago. I have just looked them over carefully with a view to improving upon them if possible. After careful thought and study I have no wish to alter or add a single note. Before writing them I had consulted the greatest cornetists and other brass authorities in the world-including the famous cornetist Jules Levy- and they were all agreed upon the proper method for improving the tone, securing power and endurance, and perfecting the technic. These exercises should in reality become the “Daily Prayer” of every brass instrument player. The playing of sustained tones is the most important form of exercise on any instrument whether it be brass, reed or string.
Volumes upon volumes have been written in the form of exercises, but nothing has or ever will be written that will improve the tone and strengthen the lips of a wind instrument player more quickly and permanently than the proper and simple practice of sustained tones regularly each day.”