Hey Christopher,
Great Question. This is a topic really close to my heart as I consider myself primarily a link builder before an account manger.
The way I create backlinks for large ecommerce platforms (1 million+ visits from search per week) has reverted back to the more traditional way of doing marketing and PR, it now just has a SEO twist to it.
Building out the assets you have on your site is key here. For example, if you are an optician, perhaps you should build out a widget that allows users to take a picture with there webcam and add the new glasses range to see how they look. Then set up a press release and contact some of the industry bloggers about it and see if they would be interested in writing about it. Then support this through the companies brand social channels.
If you are a local business, I would say you need to go back to the 1940s ways of doing business and get to know your neighbour and start giving back to the community in order to get those prized links. For example, if you are a removal service in a University town, you should be offering students big discounts on your service and contacting the university to get them to link to your site in the online student starter packs.
Basically, building a value proposition and telling people about it is the new link building tactic. It's the only thing that is truly scalable and search engine safe.
All the other tactics like guest posting, PRs, blog comments, directories all still work, but the approach is totally different. You just need to be much more selective about who you choose to interact with and where you spend your time.
I made a video response talking over this. Apologies for the lack lustre voice, I have a cold right now.
http://youtu.be/ZVP0DAEZrdo
Cheers,
Ross
ZVP0DAEZrdo