This may seem like a light post, but it's entirely effective. Lately some of the best links I get are because I ask someone I know or have met, or networked with.
I have an almost 100% success rate doing this. And in many cases, the link offers I get exceed my expectations. And I get links where I didn't think I would get them.
Yesterday I called someone I had networked with last year. While chatting, they disclosed they don't offer other people content on their website. I asked for a link anyway.
People don't want to say no. And this person didn't. They reminded me that they right for the news column of our largest national ISP (who's news page is the home page of most of their customers). Can't give me a link from their site, but they'll interview me for an article on my niche that they're writing next month. If it's a good article, it may make the homepage of the national ISP. And yes, they'll give me a link from the article.
So call someone you know that you've not asked for a link from - and ask.
Which ties into the second thing I'm finding - don't take no for an answer from a webmaster. My single best link was denied by the webmaster - I kicked it up top for reconsideration and got it approved. I'm now working on a gov't PR9 link that got denied. When I asked for reconsideration, they said what I missed was a detailed outline of how my site met their guidelines. I haven't taken that step yet, but I will. Because once they start quoting guidelines, they have to pretty much follow them - and even if they resist there's a good chance you can wear them down. Eventually I'm hoping I get this link just because it's easier to give me a link than keep dealing with me.