This may sound obvious but if you find yourself using complicated coding to achieve your design then you should think again about whether the feature you need is really necessary or if you're just thinking about your design and not your visitors. Too often designers get caught up in their own design and go to great lengths to produce a certain visual effect only to find later on that visitors find it either irritating or unusable.

Complex code is usually the result of muddled thinking. Plan your layout logically and work from the outside in and from the top down where possible. Look at what containers you will need and break jobs down into smaller parcels. I usually start with a page wrapper and then progress logically through the header, navigation, main content and footers etc trying to preserve the flow of the document as much as possible

While good visual design is necessary to attract visitors you must still have good content and a usable and accessible site. If you find your html and css looks like spaghetti then have a re-think and see if you can simplify it. This will make it easier to maintain in the future and will often save code and bandwidth.