Do a search for a website validator. Some search engines use meta tags and measure your keyword density.

Examples:

Yahoo and MSN use meta tags and keywords
Google uses link popularity and content

Submit your site to Google, MSN, Yahoo, Yahoo Directory, and dmoz.org to start. Then start exchanging links with relevant websites which will help you in Google, notice I said relevant sites.

Get a free blog from wordpress.org added and a forum like phpbb added to your website to add more content. The more content your website has the better, you're bound to type something that gets a hit from the search engines.

Updating content is like super important for your website.

Good Luck