l'll tell you how - from the peers who got in: they wooed the researcher they wanted to be a slave to. The only way to set yourself apart (from other stellar applicants of same caliber) is to court a researcher who is accepting students the incoming fall, for lack of better words. That prof will then vouch for you in the selection commitee. All things being equal, the only way to get "noticed" is to become noticeable. Although i had 7 publications at time of my masters, once in position to move on to the doc, I had no desire to kiss up (I can't find any other expression) and to someone for whom I'd give good lab hours for, even if I was interested in their reasearch or furthering their career. Im not saying this last point is common everywhere, but I do have a dozen horror stories I've heard.
I settled for a PsyD at a well rspected school and could not be happier, ..it lead to a nuero psych research at the va and the rest is history.
Perhaps the other "how" of stellar candidates getting in... is just sheer luck and maybe a 1600 on the gre