What are Back-links?
A good back-link is one that links to a site that is similar in theme to the one that it points to. If you have an authors blog for instance, finding other authors who are willing to “back-link” to you is a good link. Finding blogs about auto repair would not be considered good. If you write a Hub-page and it pertains to your regular site, you can include that as a back-link. You could maybe do it regardless, but I’d be hesitant to do so myself.
You can list your sites in directories such as Yahoo, DMOZ, Top Blogs and Blogadr to name just a few. Do a search engine search for more and maybe find some people willing to do back-links to yours for a back-link to theirs.
This is something well worth doing. Don’t just haphazardly link to just any site. It is best to link to sites that are similar to yours.
Go forth and back-link. Responsibly, that is.