No page title
Effort to fix: Quick win (under an hour)
Why it matters
The title is the headline of your search result and the label on the browser tab. Without it, search engines make one up.
How to fix it
Add a unique <title> of roughly 30-60 characters that says what the page offers, with your brand at the end.
On WordPress
Make sure your theme supports title-tag (add_theme_support('title-tag')) and set the homepage title in your SEO plugin.