So you have typed in a search to Google and it returned several hundred million results. That is an awful lot of pages but more often then not you can find what you are after in the first page if not the first few results. Google doesn't present the vast number of results randomly but instead ranks them according to an algorithm. Search engine optimization (or SEO) is the practice of getting your website in those first few ranked items in the search engine results page (referred to as SERP).
There is no knowing exactly how a search engine such as Google or Yahoo applies its ranking algorithm, not surprisingly they are highly secretive about the formula they use. As a result search engine optimization is partly a science but mostly an art. It has become more a matter of online marketing rather then computer science.
What happens is that a search engine, such as Google, will use 'spiders', which are automated software programs, that crawl around the internet going from link to link scanning each page as it goes. When it scans it looks at hundreds of different factors. Among these are the words on the page and how it they are positioned. From this the search engine will get an idea of what the web page is about and what ranking to give it.
There are experts who offer SEO services but there are also a number of SEO tools and tricks you can use personally. The two basic techniques are link building and keywords. However there are a number of other factors such as the age of the site and page structure.
To maximise your SEO you need to do some keyword research. This is something you need to spend a fair bit of time on as it can be a bit tricky. Generally you need to have an idea of what search terms people will be using to reach your site. A good tool is one by Google, here. There you can put in some words or phrases, or even a webpage and it will show popular search terms and the level of competition for each.
The search engines spiders will pay attention to keywords in your web page, looking at density, placement and consistency. So now that you have some good keywords you need to make sure that they are present on your website. You need to make sure that primary keywords are near the top and in important places such as titles.
When the spider is crawling your page it takes note of all of the links that lead to the web page, called backlinks. By doing so it is trying to get an idea of how authoritative your webpage is. It focuses on several factors.
Quantity of backlinks
Quality of backlinks, determined by the linking website
Relevance of text in the hyperlink to your webpage
Good backlinks to your site are critical to good SEO. Writing articles on sites such as infobarrel and trading links with other websites is a good starting point. Eventually you will need to get natural links â€“ people who link to your site because it has something of value.