As I wrote in various articles, organization is one of the 3 key requisites for successful automated testing, the other two being test design and automation architecture.

Divide and conquer was a strategy successfully employed by ancient Persian kings against their Greek enemies. It is a strategy that can still be used successfully today. Fundamentally, by dividing something into smaller more manageable pieces (in the case of the ancient Persians, they divided the Greek city states), it becomes much more manageable.