Okay... Sorry for spamming your chat.
I think the most important aspects are:
* camera and detecting the other player
* maneuverability and movement control
If that was you I was fighting just now, you might see that I took control of the map by walking backwards -- keeping the enemy in my sights as much as possible.
And then... when we were in close contact, I strafed at a weird angle of a jump so that it was hard to know where I went. Hoping to land me an easy hit on a confused opponent.
The C toggle helps a LOT when you're on top of a building and are trying to peer over the edge at oncoming foes jump-boosting up the side to you.