Well, I ain't the one to talk on this subject. Never been above 1250. So this is for YOU. The exemplary example who has risen above the aristocratic cream to teach us plebs how to suck on your strategical teat.
This game is a real free to play, because paying doesn't improve your rating. Paying is a way of showing support to the devs, nothing else. And CH is one of the best game around, imho, well worth being supported. [EDIT] ok you're only asking for build without legendaries, right ? go read the forums, you can do that much, can't you ?
I haven't paid a dime, and I'm pretty good. The best advice I can give is to learn about positioning and passing as much as possible, and learn not just what the best items are, but WHY the best items are so if needed you can find substitutes or alternatives for yourself.
Win, don't be agitated over losing, and keep playing so you'll eventually have everything. Time spent getting everything varies from player to player, I am not responsible for gaming addictions.