What this preview checks
The tool measures your text in the font Google's results use and compares it with the width available on desktop and on a phone. When text would run past the edge, the preview cuts it with an ellipsis, as the results page would. The meters show how much of the space you are using.
Writing a snippet that earns the click
- Put the query near the start of the title. If the title is cut, the words that matter survive.
- Say what the searcher gets. The description is not a ranking factor, but it decides whether a ranking turns into a visit.
- Make each page's snippet unique. Templated titles across hundreds of pages are the most common on-page problem I find.
The full method is in how to write title tags that earn the click, and rewriting titles and descriptions at scale is part of my on-page SEO work.