www.google.com/webmasters/tools/home
—Google Search Console, for submitting site URLs for crawling.
—Google advertising platform with keyword planner tool.
—keyword idea search tool.
moz.com/learn/seo/what-are-keywords
—background on search keywords.
—tools for keyword ideas and external SEO research.
www.w3schools.com/tags/tag_meta.asp
—additional HTML tags for internal SEO.
www.w3schools.com/tags/att_img_alt.asp
—HTML tag attribute for adding keywords to images.
moz.com/learn/seo/domain-authority
—background on how sites build reputation in search results.
—example of an email marketing service with a free service level.