Honestly, it all depends on your personal preference. I'd suggest 3.03s, for someone who's, for lack of a better phrase "middle of the road". Proms should work good, for you.
Dont go for Dulzians unless you can aim rather well. They become surprisingly effective when coupled with a good aim and some crafty dodging. I'd only suggest 2.00s unless you're effective at dodging.
As for improving yourself, there's pretty much only one way to go - practice (yeah, I know that it's been said before)