Matt Birchler of Birchtree:

Control Center can be rearranged. This is a minor change, but one that you will probably use once and then never again. At the bottom of Control Center is an “Edit” button that allows you to shift these buttons around however you’d like.

Newly released watchOS 5 is full of little tweaks like this one in Control Center. If you want a comprehensive list of the additions and changes, this review is a must-read. It’s thorough, but also very skimmable if you want to use it as a reference.