Imagine for a minute that you’re a librarian. But not a normal one. You’re a librarian for every book in the world. People depend on you every day to find the exact book they need. How do you do it? You need a system. You need to know what’s inside every book and how books relate to each other. Your system needs to take in a lot of information and spit out the best answers for a patron’s questions.

It’s not an easy job. Search engines like Google and Bing are the librarians of the internet. Their systems collect information about every page on the web, so they can help people find exactly what they’re looking for. And every search engine has a secret recipe, called an algorithm, for turning all that information into useful search results.

Now, if you own a website, search results matter. When your pages have higher rankings, they help more people find you. The key to higher rankings is making sure your website has the ingredients search engines need for their recipes. This is called search engine optimization, or SEO. As it turns out, most of the big ingredients are known.

Let’s take a look. First, words matter. Search engines account for every word on the web. This way, when someone searches for shoe repair, the search engines can narrow the results to only the pages that are about those words. Second, titles matter. Each page on the web has an official title, but you may not ever see it because it’s in the code.

Search engines pay a lot of attention to page titles because they often summarize the page like a book’s title. Third, links between websites matter. When one web page links to another, it’s usually a recommendation, telling readers this site has good information. A web page with a lot of links coming to it can look good to search engines.

But some people try to fool the search engines by creating or buying bogus links all over the web that point to their own website. Usually, search engines can detect when a site has a lot of them, and they account for it by giving links from trustworthy sites more weight in the recipe. Fourth, the words that are used in links matter too.

If your web page says, Amazon has lots of books, and the word books is linked, search engines can establish that Amazon. com is related to the word books. This way, when someone searches for books, that site will rank well. Lastly, search engines care about reputation. Sites with a consistent record of fresh, engaging content and growing numbers of quality links may be considered rising stars and do well in search rankings.

These are just the basics, and the recipes are refined and changed all the time. Good SEO is about making sure your website has great content that’s supported by the ingredients that search engines need for their recipes. I’m Lela Fever, and this has been Search Engine Optimization, explained by Common Craft.

Learn more about SEO at Search Engine Land.