Me to every SEO I have hired since 2005; "build relationships first then build ( ask for ) links"
...and it works
I haven't sent a link request email in 7 or 8 years. I pick up the phone and ask for the link.
There has been much talk in link building over the years of becoming an authority in your niche, paticipating in online forums, blogs etc and I am sure it works but participating in your offline community had always worked better for me
Attending industry conferences, events, networking organising informal get togethers, going for lunch with competiors, SEOs and marketers, attending local tweetups and just meeting for a beer and a chat has generated more of the links that I wanted than any number of link request I could have sent.