Disable Apache's DNS Lookup
Each time a web server receives an HTTP request, it saves this information in a log, generally translating the user’s IP address into a domain name. This conversion (DNS lookup) is one of the Apache HTTP server’s bottlenecks and should therefore be disabled.
Minimize the number of CSS files and compress them
Minimize the number of CSS files to reduce the number of HTTP requests. If several style sheets are used on all of the website’s pages, concatenate them into one single file.
Some CMS and frameworks offer ways to do such optimization automatically. The HTTP server can also be configured to compress and reduce the size of style sheets (see best practice #79).