On iTunes, the title track of The Best Damn Thing is the most downloaded song after Keep Holding On, Girlfriend and When You're Gone, so that might be a single if Avril's label makes their decision that way, but hopefully they won't... That's how We Ride became a single and it flopped.
Here's the order for the rest of the songs from most downloaded to least downloaded on the explicit version:
Innocence
I Can Do Better
Hot
Runaway
Contagious
Everything Back But You
One Of Those Girls
I Don't Have To Try
I doubt that the last 4 will become singles. Obvious, Hot is guaranteed (

), and I think Innocence, I Can Do Better and Runaway are definite candidates. Based on downloads and fan response, here's how she should determine her order:
4th - I Can Do Better
5th - Innocence
6th - Runaway
ICDB should be an international release, and Innocence and Runaway should be released at the same time, with one in North America and the other in the U.K., and then switch like Promiscuous/Maneater.