Pages display correctly. Text is easy to read. Background doesn't interfere with text. Graphics and multimedia have a purpose, add to the instructional value. Site uses thumbnails for large images and tells you how big the images are.
Downloadable files are easy to download.
If a file is very large, its size is indicated. Site invites feedback and provides an e-mail address. The URL is included on each document. You can submit sensitive data securely. Creates good first impression.