It should take you no more than 90 seconds to read the last four paragraphs of this interview with Debra Mastaler from Alliance Link. If you want to learn how to build links read this, then read it again. (Copied below for your reading pleasure)
You have a new product and want to use it to build links. Before going public, you do a soft launch to your customers with an invitation to link and incentive (sales.) You then run a national contest (promotions) and announce it via press release (publicity). You also send a release announcing the winner.
While the first part s is going on, you instruct your copywriters to create a humorous piece of link bait which is launched on Digg and a handful of other social media sites (promotions). The linkbait has a tie-in to the contest. (promotions) A blogger outreach program begins and offers free samples of the new product and an invite to review or send rate cards with advertising opportunities (promotions). Once the reviews come in, bundle them, and send release showcasing the successful launch. (publicity).
Based on the success of the launch, have sales and copywriting staff write a case study/white paper referencing the process, reviews and customer feedback. Offer white paper to key journalists before going public, (publicity) and then add the paper to any content source that will take it (promotions).
And so on. By the time this link cycle is complete, you will have touched on almost every facet of marketing without having to purchase a single link or having any one of the tactics stand out. Balance is key.