Although the technicalities of metatags are important, even more important is metatag strategy. Let's look at the bigger picture. On the Internet, people type one or more keywords to find you. In response, search engines list pages with the most keywords. You get additional brownie points when the first 200 words equal your metatag description.
Further weight is given to links leading to more keyword content.
In the best strategies, keywords dictate the site design. Robots are smart. They check everything. To counter this, dedicate one or more pages to every keyword or keyword phrase used to find you. Allow the larger scheme to influence your writing style in developing the page content.