Mac: Change the default application for a file type

On OS X, I wanted to change the default application for opening .txt file. I tried selecting a different app through Open With > Other... > Always Open With. But apparently that option is specific to the file I selected, not for that file type.

To change the default application for a file type:
1. Right-click on the file > Get Info
2. Expand Open with:, and select the desired app