Ideally promotion of your website to be linked to the other sites with the same niche. So you receive qualified traffic (visitors interested in the subject presented).
You can subscribe free directories site on the Web. But do not accept reciprocal links. They use you and others like you for their own promotion. If your website traffic is low you end up losing almost all visitors.
When you enroll in guiding choose the right category, a neighborhood right will help to a better positioning on Google.
Do exchange links with sites that offer the products or services you offer.
Exchange your links with your vendors and suppliers.
Write articles about your field of expertise and offer them for free to be posted on other sites. Make sure you include a valid link to your site and a short description. Lets keep copying the link provided.
When you write short news press releases and send them e-mail the editors of various publications that have online versions. Write them so that they can be posted directly without adaptation. Obviously, includes link and description.
Post in forums that allow you to insert a link or even mention the site address. Be careful not to get off-topic.
Pay for the link to your site will appear on those sites they consider authorities or experts in your field.
Besides direct traffic brought by links, quantity and relevance of these are important factors in the algorithm used by Google to evaluate a site and to establish the position in the list of results.