Here are tips to help you get higher and more frequent placement in searches on the internet:
Keywords, Metatags and Page Descriptions
Metatags are keywords that are only seen through viewing the source of a web page. They are added to help search engines like Google, Yahoo and MSN, index pages into appropriate categories for future searches. They need to be added manually in most cases, but some online applications have plug-ins that allow them to be pulled automatically from things like page tags (WordPress’ All in One SEO Pack is an example). They should be included on every page in your website, however should be relevant to the specific page they’re on, unless it’s the homepage.
Title Bar Text
Make sure you add more than your company name in the title bars of all of your web pages. Title bar text appears at the very top of all web pages. They are indexed by search engines, along with Metatags. Title bar text should match the content on each of your pages.
Image Alt Tags
Search engines can not index images, but they do index Alt Tags that appear within image tags. They look something like this:

The “imagfile.jpg is not indexed, but the alt tag “John Smith singer in Missouri” is.
Source : - http://www.byhandmedia.net/2008/07/19/keyword-marketing-on-the-web/