At first glance, the way the Apache mod_rewrite module handles query strings can be a little intimidating. mod_rewrite works by sitting on your server in a file called htaccess, and “catching” requests for URL‘s. It then checks these URL request against a series of rules and conditions you have set. If the request meets any of the rules and conditions, it applies then necessary changes to the URL, then reprocesses the request with the changes you have directed. Read more – ‘Apache RewriteRule and query strings’.
Setting an Expires (or Cache-Control) header in Apache will help speed up your website. I'm running Apache 2.x, and define an expires header for all of the site's static assets (images, stylesheets, and scripts). Read more – ‘How to Set an Expires Header in Apache’.