Here are a few nuggets that helped me over the years.
Run. Wind instruments are an aerobic activity. The lead trumpeters who play high and loud all night long do it with air. The diaphragm is much larger and stronger than the lip muscles and therefore should shoulder more of the effort. My teacher said some pros run a lot–“Ten miles a day, my friend. Get serious.”
Every day you don’t practice, someone else does. My middle school band director told me that one. In the cutthroat world of high school Allstate auditions, this was very much true. People improved quickly, and nobody led by more than a length.
For every day you don’t practice, it takes two days to get back to where you were. My first band director told me this one. When you’re ten years old and have been playing for a week, it’s reasonably accurate, though there was no attempt to quantify “where you were”. Half a decade later my private teacher said it was more like riding a bike; you’ll start off wobbly and get tired soon, but you still know what you’re doing. On the other hand, Håkan Hardenberger said in an interview that each day we must learn to play the instrument from the beginning. We’re mortal, so another way to look at it is that you only get to play for some fifteen, maybe eighteen thousand days; you don’t want to miss too many.
Pay attention to dental health. True, a brass player should rely on wind and lips more than pressure, but I’ll be past my peak the day I start losing my teeth. In the long run, dental health also is important for heart health, which you need for running.
Listen to recordings, but play with other people more. You need to be steeped in the literature and hear how professionals play. You need to listen to recordings of yourself; it’s very motivating. However, you get much more information, a firehose of it, from playing with other people: you watch as they do it in the moment, and you get immediate feedback on everything you do.