Each of us adheres to an education principle that will act as a north star. This principle is often modeled after or against how we were raised.
To some, this principle emphasizes the authority in parental authority: "My kids do what I tell them to because I tell them to do it." To others, the guiding principle is one of full agency of the child: "My kids are human beings; they know what's best for them." And the majority of people have principles somewhere between these two extremes.
The guiding principle informs how we communicate with our children. Are you asking your kids to clean their room and include an ultimatum? Do you ask them to do it in exchange for a reward? Or do you go the diplomatic way and negotiate or try to reason with them?
What works with certain kids at certain ages won't work with others. And what worked today might not work tomorrow.
You, my friend, need to adapt.
You must become a researcher—a hobbyist social scientist who observes your kids carefully and tries new tactics and communication methods to influence your child positively. Not in a manipulative way but in a fully benevolent one.
If your two-year-old son was born with a sense of rhythm, encourage him to dance his way to brush his teeth. If your nine-year-old daughter is competitive, time her laps around the house to get rid of the excess energy!
But no matter what works today, be prepared to search and find another way tomorrow.