Add relevant, authoritative content to your site. If your content is useful or insightful to your readers you may get links from other sites in your niche or from general interest sites.
Share your site or your site's content on social networking sites that you participate in. You don't want to overdo it and have your friends, fans or followers think that you are a spammer, but a few relevant mentions could produce significant social networking traffic.
Contact sites within your niche to see if they will link to your site. Use specific keywords such as your site's name or phrases that you want to rank for within the search engine as your anchor text.
Develop "linkbait" content that people want to link to. Lists, resource lists, images or free tools are all examples of linkbait content that can build SEO links to your site.
Post at blogs related to your site's niche as a guest blogger. Guest bloggers can usually link to their site at the end of the blog post, building relevant and authoritative links to the site.