I wouldn’t consider myself a pro by any means, but the best tip I can offer is slow down. Even at a walking pace the zombie AI can’t keep up with you once they are grouped up(unless you’re in mud of course), and with stamin up you’re even faster. Train at a walking pace; if you need to run ahead do so, but try and anticipate their next move. Zombies is basically a way more advanced version of the game snake from the old nokia phones. Understanding the path and being aware of your environment are all you need(how many times have you died because you got caught on the random obstacle on the ground). The difference between you and I and a high round player boils down concentration, determination, and time dedication.
Tight circles/clever corners