OK... Content is King but that doesnt mean a Blog doesnt need SEO. Depending on how Your Blog is run SEO needds can vary. I use Wordpress and tweak it in several ways to be more seo friendly.
NO H1 Headings in the Header of the Blog !
Change Wordpress Permalinks to insert the Post Title into the URL of the Post
Delete the Blog Name from the Page Titles except for the Home Page.
Use H1 H2 and H3 Headlines inside Your Post and put Your main Keyword in there.
Use the alt attributes of images to insert your keywords
Thereare some more tweaks You can apply.
Maybe You will want to read my Hub about how to seo wordpress for instructions on how to do the things described above and more.