If you are considering starting a blog, the first thing you need to do is decide on a name. There are many online services that allow you to search for available blog names and register them if they are available.
However, if your chosen name is already taken, it might be difficult to find a suitable replacement.
The best way to determine if your chosen blog name is taken is to perform a Google search. Type in your chosen blog name and see what comes up.
If there are already multiple blogs with that name, then it is likely that someone else has registered the name and you will not be able to use it. If there are few or no results, then it is most likely that your chosen name is available and you can register it with Blogger or any other online service.