One of the great benefits of using a good system like Joomla to organize your web page is that you don't really need to think about how things look when you're creating content. We think about it once, when we set up the site and organize everything, and after that it takes care of itself. This leaves you free to think about the words. Here are a few basics:

• Use short paragraphs. It's very easy to break them, and information looks a lot better on the screen and is easier to follow if it is broken up.
• Use less words. It goes along with the short paragraphs - if you can say it with less words, do.
• Use accurate, short headlines. In print, a headline is a great place to use a little creativity. For various reasons, this doesn't work as well online.
• Bulleted lists are very easy to follow on screen - isn't this one working?
• Highlighting makes it easy for people to see your main points.

If you're interested in more detail, you may wish to read this nice little article on web writing: http://www.dartmouth.edu/~webteach/articles/text.html, or this one on blogging which is dogmatic but otherwise good: http://www.alistapart.com/articles/writeliving/.