Search Engine Google, at least judging from its last update, favors .gov and .edu backlinks.  They tend to be more favourable with getting PR(pagerank) and the more  link juice flow when these types of domains are involved.

How to get these backlinks?

Stage One:

Do a Google search using these parameters –

site:.edu inurl:blog “your keyword”

site:.gov inurl:blog “your keyword”

Step 2:

Filter, Filter, Filter.  This is probably the most important step since you can collect all the links you want but if they are nofollow they will not do you much  good but add anyway hopefully you will get some traffic anyway.  The key to good “link shopping” is a well thought out, objective-based approach.

If you use firefox I would suggest using a plugin called “nodofollow” as this can save you ALOT of time looking at the source code looking for the “dofollow” tags!

For those who are years behind by not not using firefox what you need to do is find a comment posted by somebody and then rightclick, view source and you will see “rel=no follow” or “rel=dofollow” just before the name of the poster