Designing a website is hard job, and requires you to think out a plan of action, and put in a lot of work to make it successful. There are many different kinds of websites on the Internet, but if you look at all the top performers with high traffic, you will notice that they all have similar design characteristics which place them as the best in the world.
Characteristics for an excellent website design:
It's important to design a website that looks attractive and is easy on the eyes. There are many important factors which determine the aesthetics of the website however the key components are quite simple. Make sure your colour scheme is easy on the eyes, don't make the person viewing your website strain their eyes to decipher the text. Make sure the text is of adequate size and isn't set to a colour that will clash with your background. Most users will not re-adjust their web browsers fonts just to read your website, so make sure your site looks good on multiple platforms and web browsers.
If your website takes too long too load, then you will drive many users away. Several things can contribute to the loading speed of your website, some considerations should be: the size of your graphics, amount of graphics, and speed of the web server. If you're website contains flash or interactive material, try to have a html / text based version of your website for slower speed users. Remember that just because you are on DSL or Cable, doesn't mean the bulk of your users will be!
Easy to Navigate
If your users can't find your pages then the website is useless. Make sure you have an adequate navigational menu or some form of linking system. The users shouldn't have to search carefully on your website to find a link, make it obvious and consistent. If you have dynamic menu's, try to have a backup of text links incase the users browser doesn't support the scripting method you use.
Probably the single most important factor for having a good website, is to have truly useful information. If you have a website about nothing, then it might as well not even be there. Try to provide as much information on a subject as you can, write it so your audience will understand it, and produce it in a straight forward manner. With most search engines today, you have to try and keep your subject matter as primary topic of your website, the amount of useful text, links, and references will directly dictate how well you will be ranked in the search engines.
With these simple rules you should be able to produce a website that will attract and keep users, provide a useful website to the world, and help your search engine rankings. If you are not a web development guru, don't worry, just try your best to follow these rules and they will serve you well.