The choice of domain name is essential.
The domain name of a site should be its most important keyword.
Normally a website does not have any problem acquiring ranking on the exact expression of its domain name and, as a consequence, it is usually the keyword that drives the most traffic to the website.
How to choose your domain name
Not too long, not too complicated!
The domain name needs to be something people can remember easily. You also need to think about the people who are going to type your URI into the adress bar.
Who is going to remember www.hkayyzrrtdz.com without making any mystakes???
Don't be a smart ass!
If your domain name is www.isellshoeshere.com, I honestly hope that you are selling shoes and not something else. Choose a domain name which is representative of your services/products.
DO NOT STUFF your domain name with keywords!
Nowadays, domain names stuffed with keywords no longer yield a real advantage within search engines results pages (SERPs). Having one keyword can help and it is always good for internet users to associate your domain name to a clear and memborable product or service.
If you have a trademark, go for it!
Already known trademarks are perfect domain names as they are associated to a product or a service by internet users.
PROTECT your domain name!
Always buy the .com extension as well as the .net, .biz and the local extension where your website is going to displayed (.fr, .co.uk, etc ...). Keep an eye as well on the DNS restrictions (can you access your website if you do not type www. in front of the domain name).
DO NOT buy something too similar to another website!
Especially if this website is in the same business as yours. Be original. You don't want to loose part of your business to a website that you have copied.
I.e. My domain name www.seo-muscle.com contains an important keyword (SEO), it is quick & easy to remember, to look for it and is representative (I hope) of the information which is displayed on its pages.