As well as the methods mentioned above, I have been using public and private blog networks this past year and have had more success with these than anything other methods.
They are expensive, though, especially the private networks.
Public blog networks I have used:
Free Traffic System
My Article Network
SEO link Vine (not as good as the previous two)
Private networks I have used:
Linkvana
Linxboss
Both of these are really expensive, though.
Hope that helps.