Design it like an organism
One of the clearest distinctions between mechanisms and organisms was given about two hundred years ago by the German philosopher Immanuel Kant. He described a mechanism as a functional unity in which the parts exist for one another in the performance of a particular function. The clock was the paradigmatic machine in his time. Preexisting parts, designed to play specific roles in the clock, are assembled together into a functional unity whose dynamic action serves to keep track of the passage of time. An organism, on the other hand, is a functional and a structural unity in which the parts exist for and by means of one another in the expression of a particular nature. This means that the parts of an organism—leaves, roots, flowers, limbs, eyes, heart, brain—are not made independently and then assembled, as in a machine, but arise as a result of interactions within the developing organism.
—Brian Goodwin, How the Leopard Changed Its Spots—The Evolution of Complexity
Always, have a picture of the whole—product or system—while designing, deciding and building. Understand, or at least have a theory of how each change or a new feature is going to affect the whole. There are a lot of techniques out there—design synthesis, design sprints, or prototyping—to visualize the whole. Better use them to not end up with a flaky mechanism.