Search Engine Friendly Design: Make sure that your website is crawlable, meaning search engines can read what is on your site. Stay away from Flash, Javascript, and other un-readable formats. Use a text navigation so search engines can crawl and index all of your pages.
Keyword Research: You need to perform in-depth keyword research to see what people are searching for. Once you can identify which keywords/phrases people are using to find your products/services you can start to optimize your site for those terms.
Unique Title & Meta Tags: You want to create keyword rich title and meta descriptive tags. Make sure that you are not spamming search engines (keyword stuffing).
Create lots of Content: Search engines love sites that have a lot of unique, keyword rich content. Add a blog to your site or produce a monthly newsletter. This will help drive people to your site and help get links into your site.
Get lots of links: Through content, social media, and other silos get as many high quality inbound links to your site.
If you are looking for an
SEO checkup list, I have created a detailed blog post on what you should look for and how you can
SEO your site.
http://www.greendotinteractive.com/blog/2008/06/your-website-
seo-checkup-8-part-series/