I've only played one game (Emperor) as China. It was my last game and China is now my new favourite civ, taking over from Aztecs.
So I won't be able to give much expert advice.
What difficulty level are you playing at?
Paper Maker is an excellent building and lends itself to a wider empire, which was new for me. I too am somewhat smitten with the CKN. Build lots, get them promoted and try for a range promotion for when you upgrade them to Gatlings.
Further than that I don't think i'm qualified to advise.
But obviously, as with any civ, play to their strengths, which are quite apparent for China:
War - excellent
Money - good
Tech - decent.