If you aren't already using it, try gzipping your content before sending it to the client. There's an easy to use .htaccess setting that allows you to do it automatically:
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/x-javascript
For more information, check this site:
http://betterexplained.com/articles/how-to-optimize-your-site-with-gzip-compression/