One of the first things that you need to do when you are starting a website is to choose a domain name. It is really important and hard to change later. Take some time to really think about it. The name needs to be available. Everyone who can register a domain name for you will happily let you check availability. A COM extension is desirable unless you are an organization or school. If you want, you can also pick up additional extensions but you will probably have time to obtain others if you want at a later date.
The domain name is important for search engines such as Google. If possible, it should contain keywords and place these at the beginning. Spaces cannot be used in a domain name but dashes can be used to separate words. That said, keep in mind that people are the ones who will need to remember how to get to your site eg antique-chairs.com is a lot easier to remember than king-Louis-XIV-dining-room-sets.com.
This is important but don’t worry if you did not purchase the SEO be-all-and-end-all of domain names. As they say, “Content is king.” It is more important to create a site that people want to visit than to have the most catchy Google-friendly name.