I coach high school teams and also teach on my own. One book that I've read (more than once) has been the single best thing to advance my understanding of "head management". It's Vic Braden's book, Mental Tennis. As both a player and a coach, this read has been invaluable for me.
The one thing that constantly echoed in the back of my head pretty much every time I'd finish a section of this book was something along the lines of "man, I wish I had this book back when I was in high school". It's full of exactly the wisdom you seem to be looking for here. I've passed copies of it along to other adults and also a couple of the kids I've coached and I've caught nothing but positive feedback from everyone.