This is simple but also highly effective:
As soon as your website is completed, you should refer to your URL wherever you publish your telephone number, i.e. on business cards, headed notepaper, brochures, stickers, etc.
The name of your domain is a crucial issue for the success of your website!
There are still expensive newspaper advertisements (often from well-known companies) that publish a URL such as http://ourworld.compuserve.com/homepages/companyxy/. The "value" of such addresses is not worth any further comment here.
However, not much better are addresses such as http://www.brown-office-supplies.com/~userxy/index.html.
Who on earth would be able to remembers such a domain name? Better are names that contain no or only few hyphens, tildes or slashes. The less the visitor has to memorize, the better.