You have some classic microformats...author, hfeed, etc you can adjust
h-feed should be on archive pages
The get the archive title and description could use markup
You can look at my iw26 theme for ideas if that helps
Look at template-tags and template-functions
I see some things that I could enhance
https://github.com/dshanske/iw26https://github.com/dshanske/indieweb-publisher
From @dshanske: