How do I do Keyword Research and On Page Optimization for a Chinese website?

Hello Folks,
I am from Anglosphere, I do keyword research and On page Optimization as an addon service to my web design service. I got a Taiwanese client and wants SEO for her website which is in Chinese in wordpress. Basically wants keyword research and On Page Optimization.
Please Suggest how should i go about doing it. Please don't suggest hire a Chinese speaking seo person. I gotta do it myself.