Major search engines use programs called crawlers or robots to index websites to list on their search result pages. They follow links to a page, reads the content of the page and record it in their own database, pulling up the listing as people search for it.
If you want to make your site indexed easily, you should avoid using frames on your website. Frames will only confuse search engine robots and they might even abandon your site because of that. Moreover, frames make it difficult for users to bookmark a specific page on your site without using long, complicated scripts.
Do not present important information in Flash movies or in images. Search engine robots can only read text on your source code so if you present important words in Flash movies and images rather than textual form, your search engine ranking will be affected dramatically.
Use meta tags accordingly on each and every page of your site so that search engine robots know at first glance what that particular page is about and whether or not to index it. By using meta tags, you are making the search engine robot's job easier so they will crawl and index your site more frequently.
Stop using wrong HTML tags to style your page. Use CSS (Cascading Style Sheets) instead because they are more effective and efficient. By using CSS, you can eliminate redundant HTML tags and make your pages much lighter and faster to load.