What is SEO??
The key is relevancy. But how do you obtain relevancy? There are also a set of rules known as an algorithm. Although all the rules to algorithm are kept a big secret, there are a few basic principles to follow.
First, understand what your keywords are. How will people find you? If your site was about dogs then your keywords would focus on dogs. How often do you use the word dog in your content? Is dog in your title? Is the word dog listed pretty high on your website? Or is there 1 mention of a dog on the very bottom? These factors all play a role. Read more about adding content
Another way that some search engines determine your "worthiness" is by popularity. If nobody has any links linking to your site, then you must not be very important. If however your competitor has 100 people linking to his site, he is considered to be more "popular". This is especially true if people linking to your website are "similar" in content as yours. Let's use the dog as a for instance. Let's say you had websites pointing to you that were from Dog Supplies or Dog Toys. This would make you seem more "popular". Read more about Link Partnering
Click through measurement is another way that the search engines determine your worthiness. If you are ranked toward the top but nobody clicks on you, then you do not "deserve" to be at the top.
So many factors to consider when building web pages but all must be considered.