My suggestion is to think of your
SEO efforts like different pieces that all make the whole. Do everything you can as a piece of the larger puzzle that will get results; submit to social bookmarks, create a lens on Squidoo, submit articles to directories, etc. etc. and all of it will add up over time to give you great rankings.
And don't forget to optimize your site itself - make sure the keywords you're targeting are the best ones possible and your site is clean and easy to index.