What factors determine acceptance to top graduate program in Engineering? Question that is really bothering me is what are the important factors for admission to top five engineering graduate school? I searched in different forums and saw people got accepted to  PhD program at prestigious school with GPA 3.40 GRE Quantitative of 165 and no publication. However I also saw people could not get in to even master program with 4.0 GPA ,good GRE score. 
I am starting to think that GPA ,GRE and even research experience are not determining factor. Can anyone please clarify this for me?
To get into a top graduate program, you typically need:


No red flags that will cause your application to be discarded.
Something that causes you to stand out from the vast crowd of good applicants with no red flags.


A lot of people seem to think that having an extremely high GPA, GRE, class rank, etc. will help, but it does not.  The problem is that such standardized evaluations address only category #1.  There are a lot of good students out there, and graduate programs aren't really interested in whether you are the best student.  Instead, they are interested in whether you have problems as a student that would prevent you from succeeding in graduate school.

The honest truth is that there is a huge amount of unpredictability in satisfying criteria #2. and you can only do so much to control it.  There are many useful things you can do to help make yourself stand out, like participating in research projects, but ultimately there are no guarantees, because you never know how many other excellent candidates might also be applying to that program in that year, and what exactly it is that will make one person's application resonate with the particular faculty member who reads it.