Good question, we ought to make this more organized. This is practically an awards poll...
I say, like all awards, you CANNOT nominate yourself or your own work. If you are nominated, however, you may vote for yourself. To keep track of this, I suggest a poll thread each month, if it's possible to Sticky each month's thread upon creation and "un-Sticky" after the poll is over. (If un-Sticking is not possible, then well, don't Sticky it at all.)
The purpose of the thread would shift throughout the month: For the first, say, three weeks, it would be used to nominate the best stories or authors of the month. The last week (and some change), the first post can be edited to include a poll of the nominated works, and at the very end of the month, the story with the most votes is published.
...lol, this system could apply to the "Art of the Month" award as well. And also to avoid cluttering these poll threads with the actual works, I suggest extra subforums for the Art Studio and Library.