• The number one rule of site architecture is getting it right the first time, if you can, set up a site architecture so you can grow and expand in the future, without needing to radically change your URL's. Keep file extensions like .html, .php, .jsp and other out of your URL's so you don't have to change them if you change the underlying programming technology (or maintain them using htaccess overrides). This can be especially hard if you change CMS's or use shopping carts, but in the end it's really worth the effort, so you don't lose the links.

• Manage your redirects. You want to use a 301 and avoid chaining them together. I've worked on site's where I've seen one URL request pass through 4 or more 301 redirects. It may work from a user experience, but I'm not convinced it works from a search engine, link equity standpoint. However if you follow rule number one and get it right the first time, you really will avoid most of this problem.

• Consolidate dead pages. A lot of times for marketing efforts pages need to be created that have a very short lifespan. Ideally you would want to keep the page up and put up a note that says the page info has expired, however CEO's, Marketing managers, and legal departments don't agree. if that's the case, redirect the URL up one level to the root, to a more appropriate page, or to the homepage. The worse thing you can do is let it 404 and lose the link equity you gained.