Hi, I have just arrive from China Guangzhou I went there for a tourist L type

and I am planning to return again but this time i want to stay a little more since my first tourist L type is only 14 days. I am asking what are the requirements, is it the same from the first timer or more easier? also what is a best advice on applying right away thus it allowed to apply a renewal visa by a day pass by or should i need to wait after a weeks or a month to pass before applying again.
I will highly appreciate for the answer, thank you!
Best regards,
Cristy