WordPress automatically orders categories alphabetically by name. For example:

•  Case Studies
•  Detox
•  Energy Medicine
•  Events
•  Hands-on Healing
•  Testimonials

However, alphabetical order may not make sense for you – you may want them listed in order of priority on your site. The Category Order plugin allows you to easily reorder your categories the way you want, using the drag and drop method. Using the plugin, I can easily get the above list to appear as so:

The Category Order plugin is one of the simplest, no-nonsense plugins I’ve used, and quite useful.