Design your pages to load within 10 seconds over 20kbps connections, which means 25kB is the maximum page size. If you do one thing, do this. Read more...
Good design is possible without lots of images. Use CSS for layout and rollovers, instead of images. Make sure your site is usable if images are turned off in the browser. Optimising the images you do have can make them a fraction of the size. Read more...
Provide easy navigation. Don't make users load unnecessary pages which are annoying for all users but really frustrating for users with low bandwidth connections. Read more
Using style sheets (CSS) is more efficient. Don't use tables for layout. Avoid using JavaScript. Avoid embedding style rules within the page. Read more...
Avoid using PDFs. If you use them, optimise them for low bandwidth. PDFs can be optimised by using vector-based graphics and minimising the number of fonts. Read more...