+ White Hat SEO +

To improve a Web page's position in a SERP, you have to know how search engines work. Search engines categorize Web pages based on keywords -- important terms that are relevant to the content of the page. In our example, the term "skydiving" should be a keyword, but a term like "bungee jumping" wouldn't be relevant.

Most search engines use computer programs called spiders or crawlers to search the Web and analyze individual pages. These programs read Web pages and index them according to the terms that show up often and in important sections of the page. There's no way for a search engine spider to know your page is about skydiving unless you use the right keywords in the right places.
Here are some general tips about keyword placement:

• One place you should definitely include keywords is in the title of your Web page. You might want to choose something like "Skydiving 101" or "The Art of Skydiving."
• Another good place to use keywords is in headers. If your page has several sections, consider using header tags and include important keywords in them. In our example, headers might include "Skydiving Equipment" or "Skydiving Classes."
• Most SEO experts recommend that you use important keywords throughout the Web page, particularly at the top, but it's possible to overuse keywords. Your skydiving site would obviously use the word "skydiving" as a keyword, but it might also include other keywords like "base jumping" or "parachute." If you use a keyword too many times, some search engine spiders will flag your page as spam. That's because of a black hat technique called keyword stuffing, but more on that later.

Keywords aren't the only important factor search engines take into account when generating SERPs. Just because a site uses keywords well doesn't mean it's one of the best resources on the Web. To determine the quality of a Web page, most automated search engines use link analysis. Link analysis means the search engine looks to see how many other Web pages link to the page in question.

Going back to our skydiving example, if a search engine sees that hundreds of other Web pages related to skydiving are linking to your Web page, the engine will give your page a higher rank. Search engines like Google weigh the importance of links based on the rank of the linking pages. In other words, if the pages linking to your site are themselves ranked high in Google's system, they boost your page's rank more than lesser-ranked pages.

So, how do you get sites to link to your page? That's a tricky task, but make sure your page is a destination people want to link to, and you're halfway there. Another way is to offer link exchanges with other sites that cover material related to your content. You don't want to trade links with just anyone because many search engines look to see how relevant the links to and from your page are to the information within your page. Too many irrelevant links and the search engine will think you're trying to cheat the system.
In the next section, we'll look more closely at ways people try to fool search engines into ranking their pages higher on a SERP.

source page:  http://computer.howstuffworks.com/search-engine-optimization2.htm