If you minimize the scrolling, chances are, your readers will get your message. A good screen size is 640 pixels wide by 480 tall. Use tables of contents. If that first screen has a table of contents viewers will click on the links to the explanatory text. Keep images small.
Large images annoy people.
If it takes too long to download, many people will never see it, as they will have browsed somewhere else. Use Web colors. The browser-safe color palette will ensure that most people will see your page and images in the colors you intended. Avoid lots of text. People don't read the Web, they skim it.