Un-Optimized files

Issue: Un-Optimized files
Another way you can speed up your sites load time is to have clean HTML, CSS, and other included files. Remove extraneous code from your files, and use CSS wherever possible. Every piece of old html code adds up in size, even if it doesn’t impact the visual site itself. I have seen many cases where links have been removed but the code remains accidentally, leaving something like:

This code, while as tiny as it is, does contribute to an increase in load time (and in this specific example, could also be seen as spam by search engines).If your site makes use of CSS, consider compressing it to save on load times. You can do this by grouping identical styles to save space. For instance:

p {font-family:Arial, Helvetica, sans-serif;font-size:12px}

li {font-family:Arial, Helvetica, sans-serif;font-size:12px}

can be compressed by grouping these two styles, reducing the coding by half:

p,li {font-family:Arial, Helvetica, sans-serif;font-size:12px}

Again this may not seem like much, but when you add this up with all of the other little things, it can ultimately result in a significantly increased load time for the page as a whole.
Audio and video can also be compressed. If your site uses a fair bit of multimedia, see if you can compress these files a bit more than you have already. You may be able to save some load time here as well without impacting user experience.

tip taken from: http://www.webpronews.com/expertarticles/2008/10/23/how-does-slow-load-time-affect-you