How to strengthen financial credit to secure loan easier as Freelancer?

Already have house loan when I was working with someone previously as salaryman. Now doing freelance and thinking of getting another house in near future. What can I do to strengthen my financial position to be secure loan easier? Thinking of getting a property about 1mil-1.2mil.

Previously heard people said that business income in current account only to be considered of 10% income?

Any sifu can teach how to prepare the document and how many months prior to purchase?

Thanks in advanced