There are two basic types of SEO. What you do on your website and what you do off your website. What you do on your website is optimizing each page for a particular keyword phase. Pick a keyword phrase, not too competitive, that is relevant to the topic of your web page and use it in your title, your meta tag description and a couple of times in the text on the page.
The main SEO you do off your website is getting links to your website. These can come from submitting your website to directories, exchanging links with other website owners, making posts on social networking sites, such as Squidoo, posting at forums and on blogs, etc.
This is very simplistic, but if you continue to search, you will find more detailed information on this.