I’m in a bit of a bind here

So after completing the story and endgame content I’m now working towards earning the Luna’s howl and redrixes. But I have a problem,

I suck HARD at crucible. Part of it likely has to d with my choice of subclass that I’m used to (Dawnblade top tree) but obviously being airborne is a disadvantage in pvp. And I’ve trained myself so much into shooting while airborne that I continually try to do it. What’s worse, I tried using a different subclass (nova warp because i figure if I’m trash an OP subclass could help offset that until I get used to staying grounded and maybe get used to another subclass

Problem is, I cannot seem to be that team killing machine that everyone makes it out to be. Or kill many people at all for that matter. I’m not sure where I’m going wrong with the super. Any one have any advice?