From example.com to www.example.com
Make sure your website does not appear when entering in the hostname without the initial www – this can lead to a 301 sabotage. This is where a duplicate penalty could be triggered and get you knocked out of google.
Put this in your .htaccess file
RewriteEngine on
RewriteCond %{HTTP_HOST} !^www\.example\.com [NC]
RewriteCond %{HTTP_HOST} !^$
RewriteRule ^/(.*) http://www.example.com/$1 [R=301,L]
