I have done absolutely everything wrong at some point. But in the process I learned what it takes to play the instrument easily and effectively.
I stretched for high notes. I didn't warmup. I injured my lip, almost quit, labored on multiple embouchure setups, looked to mouthpieces and equipment for answers. Tried a rolled-out embouchure, rolled-in, puckered, high placement, low placement, side placements, excessive aperture control. It was a sad laboratory of trial-and-error experiments and I was the rat.
Over the years I've found that trumpet playing can be simplified into two functions:
A solid, intense, unrelenting, but relaxed! flow of Air. A breath and exhalation that allows this to happen. Posture that allows this to happen.
The tongue plays a tremendously important role in regulating the speed of the air. For the high register, the back of the tongue must form an "ee" position, thus creating a sizzling sound of fast moving air.
Don't think about the Lips. Think about the Air and how the tongue is controlling the Air. The Air feeds the Lips. When properly set in front of the air, the lips will react to the air and create the necessary buzz.
This does, however, require an efficient setup. This setup (lips and jaw) is defined by gently locking in the corners and finding the easiest, most efficient free buzz (without the mouthpiece.)
There are lots of ways that I cannot free buzz but still play the trumpet; however, these are less efficient ways of playing. There is exactly one way in which I can free buzz cleanly and flexibly, and therefore it is of prime importance to carry this efficient free-buzz setup over to the trumpet. And then just blow and sing. And forget about the lips.
#2 must not impede #1 or take priority, as is often the problem.
The throat is another problem, as it often can impede #1 (monitor this through exercise of #2).
Speed of #1 is very important, as it must work in sync with #2 and change throughout registers (high notes = fast air). Again, posture must facilitate the changes in air speed.
All other techniques stem from these two functions.