Keep graphics small in size. Smaller graphics have less bits to transfer and load faster which means less waiting for the user. Only use graphics that are absolutely necessary.
Limit the number of graphics used. You may have small graphics but if you have too many, it will still take a long time to download all the files.
Use 16 colors or less in your graphics. Black and white graphics are smaller files than color graphics. A black and white graphic that is drawn in a color mode may be up 16 times larger and 16 times slower to load.
Decide on a format that you are going to use for all publications. This will determine the overall "look" of the institution. Make sure that all web page creators have input to the format and that they follow the format.
See what other web sites are doing. There are a lot of web sites that have good ideas. There is no use re-inventing the wheel.
Avoid dramatic colors. If you can't read the text because the colors are off the wall than you've wasted your time.
Keep the pages to a reasonable size or provide local links so that users can move around the web page easily and quickly.
Avoid movies, animations and sound clips unless otherwise absolutely necessary. All take large files and long times to download. The key is to avoid any unnecessary waiting on the user's part. It is very frustrating to wait for 5 or 10 minutes to download something that is not necessary.