In relation to a website it implies making such changes as to make it more important than other similar sites so that the search engines rank it high in their search results for a given search phrase.

Before beginning search engine optimization of a website one has to determine what search phrases are used by the surfers for their search. Stick as close as possible to these.

A site may require more related unique content to be added in a way that search engines robots find it easy to index the website. Of course algorithms of the search engines have to be kept in mind while optimizing a website.

Especially important is not to use techniques that prevent search engines from fully indexing your website and are disfavored by the search engines. These are known as BLACK HAT SEO. On its detection, your site may be removed from the listing.

Search Engine optimization can involve the following and many more factors: - 1. Content in the body
2. Title tag
3. Description tag
4. Keywords tag
5. H1 --- H6 tags
6. B and I tags
7. ALT tags
8. Link popularity

Link Popularity implies the number of websites that link to your website. Building up link popularity is a very time consuming task. Websites have to be searched for to know if they exchange links; then they have to be emailed with a link exchange request. Response rate to these requests will average around 2 percent. Then links to responding sites have to be published at your website and URL of that page informed to the partner site. Further follow up involves receiving URL of the location of your site's link. You then must confirm its actual presence by visiting that page. A painful process indeed But NO MORE

A fully Automated FREE Service is available at www.toptenserp.com. No pointer to this www.toptenserp.com will exist at your website. You will continue to get link partners even during your sleep.
First, think about the theme of your site and write down the words you would use your self when searching for a similar site. Now if the sites you expected came up then you have got a good list of keywords ready to build your site content around.
Do not make your content TOO keyword heavy though as this will result in a penalty from the search engines, there are lots of free tools available for you to check your keyword density and they will tell you what state your site is in regards the keyword situation.
Another good tip is to check your competitors who are getting good search results, view the source code on their page and make a note of their keywords, now have a look through that pages content to see what kind of keyword ratio they have. Do not copy a competitor's keyword and content per se, but use it to your advantage. A lot of websites tend to take their foot off the gas once they have a good search engine position. You need to put time into this constantly to stay ahead of the game.
Use Google's webmaster tools they are there to help you. Make sure your Meta tags are correct, poor Meta tags can affect you more than you think. Once you have good keyword density then you need to start building up traffic.