At the moment a contest is closed a winner is determined: the entry with the highest final score wins, other entries follow in a descending order by score. Number of votes is not a key factor in the determination of the final standing but is quite important in calculating each entry's final score.
Let's see how the final score for each entry is determined:
An average of points assigned by voters with each vote on a given is calculated determining the entry's score (Sum of all points assigned / # of votes).
Each entry has its own Score ratio which is multiplied by the entry's score to determine the Final score.
The Score ratio can go from 0.0 to 1.0 and is calculated by comparing an entry's number of votes to the contest's votes average per entry (Total votes cast in the contest / Number of entries in that contest with at least 1 vote). If your entry has a number of votes that is at least 75% of the contest's vote average your ratio could reach 1.0. The Score ratio is also affected by how many votes you cast in the relative contest: whenever you participate in a contest a "Vote progress counter" will appear in that contest's page, showing how many votes you should be casting to reach full ratio. Failure to cast this minimum amount of votes will result in a penalty to the entry's ratio of 0.1.
Each entry can have a Honour penalty ratio which negatively affects the entry's score ratio, preventing it from reaching the full 1.0 (See Honour).
So, basically, Final score = Points average * (Score ratio - Honour penalty).
The Score ratio of any given entry can change during the course of a contest, depending on the voting pattern. In turn, the Honour penalty can change only if the entry's author gains enough Honour to render it null by voting fairly in recently closed contests.
If you have more questions ask here or read the f.a.q. pages