^^Have not gotten around to reading this but I'm looking forward to it. Great excerpt.
For me personally, the biggest strides I've made in my game this year have been mental. It's incredibly hard to focus for 1-2 hours at a time, but I have worked really hard at it and it's paid dividends. I think running long distances has helped me with this. Also, I do not let my mind wander during matches. I focus on things like my strings, the balls, my shoelaces, etc. to keep me from doing so between games & sets.
I know I have an opponent on the ropes when they start looking at the court next to us between points and games. I have them right where I want them!