Many may wonder why some people got #1-3 quite often during a keep raid and asked how you could improve your own contribution/ranking during a keep raid? Most people on official Forums may told you to actively participate on the keep raid, don't go afk and do as much damage/heal/tanking as possible will make sure you're on the top.
However, this is not completely true. Mythic was to stupid to develop a full functional contribution system which will reward people accordingly to their effort in the public quest/open RvR. Instead they simply determinated the player will get a hidden roll each time he enters a certain zone/pairing which will determinate his contribution.
This was confirmed by many peoples on the Warhammer Alliance forum. Some people always got #1 in 3 different keeps (within the same zone/pairing) 2 out of 3 times with being half afk and not doing anything at all.
Basically: If you're on a low rank (let's say 10-30+), your best bet is simply to zone out and zone in again (log out/in should work too) to get a new "hidden roll" associated with your character.
(Source: Warhammer Alliance Forum)
There is also another cheat/exploit you can use, to increase your chances. It's also quite easy and really not understandable how stupid this guys over there at Mythic are to program such a shit. If you're using the ram on both gates (jump inside and use it and not just place it down or attack the gate with your skills) the chances are very good that you will land at ranking 1-3 each time.
Happy gold bag grabbing
Update: Another proof for the theories above (click for zoom)
So how could a chicken, do enough damage to get silver medal and roll high enough for #1?