Isnidar, I would recommend you look at the sites of major universities. Google keywords like "university writing center" and you will get a ton of resources, in many cases downloadable for free. Here's an example:
http://uwc.ucf.edu/handouts.phpI teach a course that is very writing intensive (AP Language and Composition) and for the writing portion I basically created my own curriculum using these sorts of handouts and presentations. If you search around you can find handouts that include exercizes, or easily create your own.
I honestly haven't found a textbook available for purchase in China that suits my needs for advanced writing students, but there are plenty of free resources online.