Godaddy domain auctions is a great marketplace for domains, but it can be hard to have success selling unless your domain is quite special (high PR, high traffic, or one-word domains). It tends to be more a buyer's market than a sellers. I would put a wordpress site on it fast and sell it as an established blog on flippa
EDIT: About promo's, you can promote your auction like any other, post the auction link on some forums, just make sure your audience is interested in domains!