This applies to all staff, irrespective of nationality. Just because "this is China" there is no reason not to incorporate the normal checks and balances that you would back home.
Check language skills both orally and written: A simple test. Some Chinese staff have their friends write their English CVs for them, while many expats overstate the fluency of their Chinese. Note also there is no such thing as "fluent Mandarin" and that regional dialects can and do enhance or limit your staff's ability to all-round efficiency.
Check all backgrounds and references: Often neglected. Often regretted later. Follow up those qualifications and references. You're paying for them so make sure they are really part of the package.
Pay staff properly: If you want to retain them, pay them properly. Not just their welfare payments, that you should be making in any event, but enough to keep them motivated and keen on continuing to work for you. China may be the current center of cheap manufacturing--but there is no reason for you to be cheap when it comes to your staff. If you are, you'll end up spending more time on recruitment operations than on your actual moneymaking operations.