There are various factors when choosing a domain name. It is natural to go for a short domain name and is connected to something that is popularly searched for by surfers so that the chances of it being found and visited form search engines (free or organic hits) are better. An example might be camera.com. This is in the hope that surfers (potential customers) are more likely to find camera.com when searching for camera. There are many domain name registrars, but don't try to register that domain name because 99.99999999% that had already been registered by someone, and if it is not already in use, very likely the one who registered it will be trying to sell that popular domain name at a very high price.
Now you can try other domain names and it will be good to do some research first like looking up common and popular key words and try to zero in on some key words related to what you want to put on your website or blog in the domain name. If you want to do that, type "keyword suggestion tool" into the Google search box above, tick the radio button beside WEB and search. You will see a few websites that can help suggest key words for you. But that is hard work.
