You can register your domain regardless of whether you have an actual web site ready to go or not. By completing the domain registration process, you can rest assured that once you've registered your domain name, it is not available to anyone else. When you are ready to create your web site, the domain name you created during your domain registration process will be waiting for you.
Tips on Choosing Your Domain Registration Name
Choose a domain name that uses major keywords for your business. Using your business name is not always the best decision if you're looking for search engine top rankings.
Keep your audience in mind when choosing a domain registration name. Just because you can use up to 63 characters doesn't mean you should. Your name domain registration should be easy to remember. This may prove to be difficult and could take time to think of a good name. Almost all 3 and 4 letter domain names that make sense are already taken.
Don't be afraid to use hyphens in the name of your domain registration. If you have a name that is more than 3 words long, hyphens will help it to make sense to your potential clients.