In my personal experience - side projects, blogging and technical articles all help; done all three, seen results from all three (for getting both jobs and consulting / training work), and intend to do more. Ebooks are pretty sure to help too. Obvious caveat is that all have to be at least reasonably good. Blogging can take more, time though, you have to keep doing it for some time before people notice it. Every little bit helps, though, IMO.