Chinese mantises are pretty easy to breed. One of the best things you can do is make sure the female is well fed, and maybe even have her eating while you introduce the male to her. Where do you plan on mating them? in a large cage? or free reign in a room?
Chinese mantises don't need any special requirements to breed such as humidity or heat. Basically just place the female in a nice spot, with food in claws, then place the male behind her and they should get to business. If they don't mate or the male seems reluctant you can prod him a little to get onto the female. If they attack each other have tweezers or something to help separate them.
Good luck!