Whether you have a personal blog or a library blog, you'll need to promote it in order to gain readers. Of course if your content isn't current and interesting your readers might not return. Not to worry though, there are plenty of online resources and blogs that can point you in the right direction.
ProBlogger is a "free collection of tips on writing content, search engine optimization, using advertising and affiliate programs etc - to help bloggers explore ways of adding revenue streams to what they do." ProBlogger also contains articles on promoting and marketing your blog. [link via B.L. Ochman].
I would also recommend Robin Good's Best Blog Directory and RSS Submission Sites for even more sources.