Other forms: systematized; systematizing; systematizes
To systematize is to organize things into coherent groups or according to a specific plan. If cleaning your room feels overwhelming, you should systematize the job, breaking it down into orderly steps first.
Whenever you arrange or organize something with a system in mind, you're systematizing. Math teachers systematize the subject before attempting to explain it to students, sorting concepts into an order that makes sense and organizing lessons so they gradually increase in difficulty. To teach your dog to shake your hand with his paw, you first need to systematize your training, starting with "sit," and working your way methodically toward your goal.