I am content if I am in accord with Nature in what I will to get and will to avoid, if I follow Nature in impulse to act and to refrain from action, in purpose, and design and assent. (Epictetus, Discourses XXII)
At its very core, the font from which all other Stoic teaching spring is "Follow nature". This is not a command to hug trees and dance with the satyrs, but to act in the manner that naturally allows us to flourish. These principals work because they are natural. Every law in the universe supports them and, like gravity, any attempt to ignore them with have unfortunate consequences.
One can understand the Stoic discipline of "Ethics" as being the study of how to correctly follow nature. To do this, one must have a solid grasp of the "Logic" discipline. And the information to which one applies that logic comes from the final discipline, Physics. The ancient Stoics understood Physics as a combination of what we would today refer to as natural science, metaphysics, and theology. More broadly, it can simply be understood as, "the way things are".
Following nature means following the facts. It means getting the facts about the physical and social world we inhabit, and the facts about our situation in it-our own powers, relationships, limitations, possibilities, motives, intentions, and endeavors before we deliberate about normative matters. (Lawrence Becker, A New Stoicism)
So, you use Logic to understand Physics, which tells you what is Ethical. Put another way, you use reason to study facts in order to figure out what to do. Or how to live.
If you understand this process, then you'll recognize that all the other teachings of the ancients are simply rules of thumb derived from the first rule: To follow nature. In any situation where find yourself at a loss concerning what is "right", if your maxims are in conflict, if you forget what Epictetus said about it, if the "rules" are counter-intuitive, your default response should always be to fall back to the source and "follow nature".
And that just means, "Use your head." If the facts change, you adjust. If you don't have enough information, you get more. If your current path doesn't make sense, you go a different direction. “Use only that which works, and take it from any place you can find it.”
There is no "orthodoxy" in a living philosophy, and you can't be doing it wrong if you're making it work.