The fifth SEO mistake to avoid is spending time on meta tags. Why? Because they really don't matter outside of your main pages. Even then, it is not an activity that you should spend a lot of time on.

Occurs when
You go through your site setting keyword and other meta tags on each node.

Fix by
It can be fixed by remembering that Google doesn’t use the keywords meta tag. Go ahead and set them for your main pages, but don’t spend too much time on it.