Keep the page simple
Use graphics sparingly and keep the page size <20 KB.

Do not make tables or images larger than 640 pixels wide
Some people still run this low resolution on their monitors and they would have to do a lot of scrolling to view the image or text.

Use relative hyperlinks within your pages.
Instead of each hyperlink being something like http://www.sdafs.org/reservor/default.htm, you can type in something like default.htm (if the page you are working on is in the same directory as default.htm).

Don’t get too fancy with frames, Java, Active X, etc.
There are still a lot of browsers out there that don’t support these things.