1) Use the SEO for Firefox plugin to analyse the Yahoo backlinks of your competition sites, as well as their age and Google Page Rank - then aim to get links on some of the same sites as your competitors, and to have a greater number of relevant links

2) Use Google blog search to find relevant blogs where you can leave relevant comments that link back to your site/blog. Try to use a unique keyword combination for your links so that they’re easy to track.

3) Use Google to search for forums relevant to your topic, and join and participate in those that allow links in your ’signature’

4) Use Google to search for relevant pages to comment in Web2.0 pages on HubPages and Squidoo.