What is the most important aspects of Ph.D. application other than previous university and GPA? I'm just curious to know what are the most important requirements for filling up Ph.D. application, generally. is job resumes important if available? Or for example GRE, Publications or Research interest? What is more important?
Acceptance into a doctoral program isn't a matter of accounting and counting chits. Someone, or a group, needs to make the assessment that you are highly likely to be successful. To that end your GPA is relevant, but so is everything you write or say as part of the process. If you are considered to be a serious candidate with a fairly easily predictable good future, you will be considered. 

After that, it can be a matter of competition. There will be a lot of other candidates that have excellent records and they are also being "weighed". 

But certainly, anything that shows past success in the kinds of things that doctoral students actually do (pubs, research) is a big plus. But don't neglect your SOP, where you talk about your envisioned future.