-- Keep it clear and keep it simple. That doesn't mean you can't have some fun and use animation or other attention-getting devices on your site, but make sure you give the visitor what he came to see: information. All of the basics should be on the home page: who you are, where you are, what you do, what you can offer.
Anything secondary can have a link associated with it. If a visitor has to wade through a bunch of superfluous information to get to the meat of things, he won't be there long. Include plenty of appropriate keywords in the first few paragraphs for search engine optimization, but don't stuff.
-- A web page needs to be easily navigable. All tabs should be legible and be worth a visitor's while. Keep your background "noise" to a minimum: use plain backgrounds with easily seen contrasting text created in a pleasing font.
Putting hot pink text on a bright red background is simply not easily seen by the human eye, and hence visitors will not stick around to try to read something they can't see. When using tabs, labels, and links: make them worth the visitor's time and effort by sending them to relevant and helpful websites. Don't insult your reader's intelligence.
-- Make sure your webhost is fast: no one likes to be kept waiting too long. Keep your graphics and animations to a reasonable level so that your site can be uploaded more quickly. Test your website using all of the major browsers to see what it looks like and to make sure it shows up just the way you want it to.
-- Update your site often: in this day and age, it doesn't take long before a website looks old hat. Keep abreast of all of the latest software that can help you to alter or make over your site from time to time: it will generate new interest and maintain your credibility in the internet marketplace.
Whatever you do, make sure to keep your users' and other visitors' needs in mind when creating or updating your site: that's the key to maintaining an excellent and effective website.