Short list of things to do for SEO
- Provide content, not just links, not just images.
- Use meta-data to describe your site and content.
- Check for broken links and correct HTML.
- Fill in “alt” in your image tags.
https://www.google.com/webmasters/tools/dashboard – submit/verify your website, create a sitemap
Completing these steps will make sure you get listed on search engines and prepare you for the next steps – marketing and building links.
See Vaughns Google search engine SERP Ranking Factors SEO Checklist for a much more detailed and comprehensive list than what I have here.
Vaughn also lists things to avoid. Which is just as, if not more, important than things to do.