Get with a trainer.... believe me could be something extremely simple.
Yeah, I plateaued a bit before I joined my current squad.
When I joined I started DA'ing them and wooaaahhhh Nelly did I learn a few things.
I went from being waxed almost straight away to being able to get on top of our DA King Prawn every now and then. He still spanks me convincingly but I do seem to put up a fight now.
Not that score means anything, but my KD went from 2.0 looking good to me to 4.0 looking
bad. I still fly head-long into big red clouds and I love to try and fight my way out of 3 v 1s, so the score thing isn't a GTR styled "Oh no, my adversary is almost co-alt, I better run 5 sectors just to make sure that I'm safe" way of flying.
Change squad, try and hook up with a squad that always slaps your around the hardest. Fly with them, watch what they do and how they fly. Go to the DA with them and get them to teach you the ways of the Force.