Sometimes some of your targeted pages or posts may not be ranking and you may be wondering why. If you do a site search (site:yourdomainhere), you can see how many pages of your site are currently indexed and what pages Google thinks is the most authoritative and least authoritative. If there are pages that should not be indexed, you can remove them and clean up your site’s index in Google.
Three ways of doing this:
You can use Disallow in your robots.txt file to prevent Google from crawling certain pages, posts, directories on your website and indexing it.
Remove URLs via Google Webmaster Tools
You can use the Remove URLs feature in Google Webmaster Tools to inform Google to actually remove certain URLs from the index. Then use robots.txt to prevent Google from re-crawling and re-indexing those URLs. You can remove directories from Google by putting yourwebsite.com/path/ into the URL text field, then putting hide directory from search results as the Request Type.
Removing URLs using noindex meta tag.
You can insert the Robots Noindex meta tag into pages or posts that you do not want indexed. But you would have to edit the files and this can be tricky if you are not using a CMS like WordPress.
Only 2 of these 3 methods can actually remove URLs from the index. 1 of these methods prevents Google from crawling the URL but does not remove that URL.
Once you have performed any of the above methods, you must go into Fetch as Google feature in Google Webmaster tools and Fetch and Render your entire website to apply the changes and watch your URLs disappear from the search results which should help with your rankings.