How to organize the list of countries at checkout

[glowboards]

This is a snippet of exactly what I want to do, when you select the shipping country at checkout. 

I was wondering how to organize this list so the most common countries I sell to remain at the top easy to find and then the less common countries my customers are located are underneath.

My store : https://glow-boards.com/ 

The store snippet I used as an example: https://www.heysilkyskin.com/