I think one of the best ways to start getting links from big sites is consistency in your own blogging in the area that they're blogging.
The people that are carefully and consistently working on their own blogs will note consistency from others who post comments (and thoughtful comments). It's a game of statistics: you find the ones that will pay off the highest when they do link, and then you start working the numbers, posting comments, and - dare I say it - even talking them up a bit.
It's a social phenomenon, and so there is no physical guarantee to anything; it's all a game of odds and fuzzy logic.