there are many type of z visa, teaching visa and non-teaching visa.

if you want to work in China, at least you should have at least bachelor degree, 2 year working experience in your own country relating to the jobs which you are interested in Chinese job market. A recommendation letter is necessary.

can examplify some samples of properties (but these are just my predictions ,I have no idea for the procedures in practise)

-- having three years of experience in the relevant area/job

-- holding/ having patent/utility model or design

-- being younger than a defined quantity of age.

-- being offered a job position in advance (prior to arrive)

-- something else and etc