when i started out i was posting some of my best photos and was getting very little response so i promoted quite a few of the posts that i thought would attract the most attention. it seemed to be quite helpful. i got some interest and that gradually grew into more, both votes and comments as well as followers. my guess is that the choice of what is promoted is key. an eye-catching quality photo or artwork would be a good choice. if you don't have that then you will probably need a really good headline.

just consider how you yourself react to the promoted posts that suddenly appear on your blog. which ones do you consider positive and which would you rather not have on your own blog.