I'm still finding that any time I have a good instructor in the car, I learn something really useful. That may be because I have lucked upon good instructors, or it may be because I only have 86 track days in my log book so far.
Also I find I can't drive very well if my brain is baked. So I paddock near the bathroom and make sure I drink enough water that I'm visiting it more than I would really like. And staying out of the sun.
It's always nice to see another person get bitten by the bug.