Just like all things related to Tri.....how do you get better at biking.....go out and ride alot......how do I get better at running......run alot, and how do I get better at swimming....swim alot. Yes there are certain drills that might help in all 3 sports but the thing that will get us the furthest along is to go out and do each sport as much as possible.
And like anything on the internet it's pretty hard to critique form without being able to see it. as Gordo Byrn (coachgordo.com) would say JFT (just f'n train).