If you've locked yourself away in a dark room, subsisting on coffee and pizza while you develop the website that's going to allow your business or idea to revolutionize the world, then stop right now, open the curtains, take a break and read this. First off, it's likely that whatever your trying to design or create has already been done in one form or another - even if your application is completely unique, the vast majority of your website will still have attributes that are common to other websites.