It’s hard to find the right domain name. Often, the one you want is taken. If you’re after a domain that is an exact match to your main keyword, you’re likely to have to bargain for it with a current owner, which can prove very costly. Not every business can afford to do this. In that case, you need to have a few more options.
Reworking a domain name
If you miss out on the domain you want, it is possible to come up with one that is almost as good. In fact, it’s much better to have a list of domains you could be happy with when you first go domain hunting. When you go looking for a domain, here are some things to consider:
Keep it short. ‘howtoregisterfreedomain.blogspot.com’ may be cute, but ‘rememberthisdomain.com’ is a little easier for Internet users to type into the address bar.
Keep your keywords in mind. It’s a good idea to have at least one of your keywords in your domain name. Having a keyword worked in at this level makes your search engine optimisation efforts to relate your pages to keywords a little easier. It must be a keyword you will use in the long term.
Keep it memorable. Your site address is the first clue the Internet user has to your business identity. If they click through and find that your site RememberThisDomain.com isn’t about how to remember a domain name, but about looking at old houses, they’ll click back.
Source : http://www.stuckon.co.uk/choose-a-good-domain-for-seo-1933.html