Search-engine optimization—the process of designing your website content in such a way that users will find it through their search-engine queries—is one of today’s essential sales boosters. After all, the vast majority of buyers now begin their purchasing research online. If you don't help search engines find your website, Web users will never find your site—or your product.

But as Scott Wilson discovered, search-engine optimization isn’t necessarily as easy as outsourcing the task to someone in the know. After wasting $16,000 on a search-engine optimization consultant who did nothing to boost the Google rankings of his video-production company’s website, the entrepreneur came up with an idea: to start his own SEO service that would recommend only those tactics proven effective by scientific experiments.

Wilson, president of Burlington, Ont.-based eMotionPictureStudios, formed an eight-person team packed with math, science and programming big brains that since 2005 has rigorously tested hundreds of propositions about what will land a site a top-30 Google ranking for a given search term.

His team’s research confirms that some well-known tactics, such as encouraging other sites to link to yours, remain key to a high ranking. But the research has also proven the effectiveness of tactics you might not know about:

1. Leverage the power of social bookmarking. The explosive growth of social-bookmarking services that let Web users share the addresses of their favourite sites offers an SEO opportunity. That’s because Google trusts sites more if visitors bookmark them. It therefore counts as a link to your site any time a user bookmarks your site on, say, Del.icio.us or StumbleUpon. Wilson advises installing an “Add This” button on each Web page so visitors can bookmark your site on the service of their choice.

2. Hook ’em on video. Google gathers remarkable intelligence about whether people are finding what they want on the sites that show up on its matches, so your site’s ranking will soar if it offers appealing downloads. As YouTube’s enormous traffic shows, video is a powerful attention grabber. It need not be glitzy or pricey; the key is to post video that’s highly relevant to the search term—and to do so before rivals cotton on to this tactic.

3. Keep Google in the loop. The search-engine giant reads CNN.com every few seconds, but might visit your site just twice a year. To ensure that your fresh content or site improvements don’t languish unindexed, submit to Google an XML sitemap, which shows your site’s coding, each time you do an update. Google will help you correct any errors in the sitemap to make its indexing more accurate, and will crawl your site more often if you routinely send it XML sitemap updates.

4. Optimize each page to a search term. Chances are every page on your website has the same title tag, the words at the top of the browser window describing the page. If they’re all titled “Acme Enterprises,” Google is less likely to realize you have a page rich with content that would interest someone searching for, say, “discount high explosives.” Put a search term in each title tag as part of a strategy to focus each page’s content and labelling on specific keywords.

5. Run photos and work them hard. A Web page with a photo relevant to a given search will outrank the same page without one — provided your coding labels it with an appropriate tag, such as “left-handed-golf-clubs.jpg,” rather than a digital camera’s default label, such as “1325.jpg.” Also, be sure to run the same keywords in the “alt text” tag that lets you describe the image for visually impaired searchers. Most Web developers leave these tags blank. Yet Google indexes them and rewards pages on which a search term appears more often—although not so often it looks like you’re trying to fool its website crawlers.