You should keep the sitemap up to date (run job) and use pretty URLs. The rest of SEO is mostly having good relevant content that contains all your key words and phrases, is well cross linked inside the site, and has good and relevant links with other sites.

Keeping metadata up to date is always good, but is a secondary issue to content. There is a dashboard page for bulk editing metadata and there are several addons, including my own Magic Heading (there are SEO notes and links in the forum pages there).
http://www.concrete5.org/marketplace/addons/magic-heading/...