Here are tips:
1. Before you buy a domain / blog, you should already have a plan on your blog, use the domain names that match the content of your blog / website. For example, you will create a web / blog with the computer as a theme, so you can choose the domain that has to do with computers.
Example: learn-computer.com, computerknowledge.com, easy-computer.com, computer-tutorials.com.
The domain name does not have a short, easy to remember and clear. In my opinion, a good domain is a long, clear, concise, and easy to remember.