URLs

There are two main considerations when considering how to optimise URLs.  

1.    Does your registered domain name include one of your Tier1 keywords?  Google gives credit in those cases and this benefit is the main reason you should start optimising even before you register your domain name
2.    You should take the trouble to rewrite your URLs so that they mirror your breadcrumb trails.  "Rewriting URLs" means converting the gobbledegook (the bits that have  such characters as "%” and “?”) into paths such as www.yourdomain.co.uk/second-level/third-level/page that mean something.