Sometimes the simplest solutions are the most effective.  For instance, our SEO company has a number of link-building strategies and techniques that we use depending on the client; however, sometimes the best way to build links is also the easiest - just ask for them.

For instance, if you are on a friendly basis with other bloggers or site owners in a related but non-competing niche, why not ask them to add your link to their blogroll or on their resources page?  Agree to return the favor if necessary.  Doing this too many times may result in a penalty for reciprocal links, but a couple dozen times over a few months certainly won’t hurt your rankings.  In addition, asking friends or family with websites to work your link into their text somehow is always a good idea.

Last but not least, simply emailing (or tweeting) bloggers or site owners who link out often and might be interested in your site could prove remarkably effective, especially if you have interesting or creative content - just send a quick email asking them to check out your website and link if they like it.  You never know, after all, a few links on popular sites could end up driving massive amounts of traffic and generating a huge buzz for your business.