Not Checking URL Canonicalization
Have you ever noticed that there are two ways you can type in a website address? You could type "www . YourWebsite . com," or you could simply type "YourWebsite . com." While both of these URLs may resolve to the same website, they are actually different website addresses in the eyes of the search engines. As you build out your website, publish content and seek inbound links, your link total will actually get split in half, as some bloggers will type your URL with the "www" prefix, and others will leave it off.
The solution is to tell the search engines to group both URLs together using a 301 redirect from one to the other. This is called URL canonicalization, and it can double your search engine power when done properly. It does not matter which URL -- "www . YourWebsite . com" or "YourWebsite . com" you choose to redirect to the other, all that matters is that the redirect is a 301 (or permanent redirect). Any other redirect type will not work.