From what I've seen, low intensity has a predictable winning scenario. When you scan all ships, you'll see a greater number of one faction than the other. If you leave and re-enter the zone, it might flip the other way. So generally speaking, if you side with the faction that has the most NPCs in the zone, you'll generally have greater odds and an easier time to win.
In high intensity zones, it's kind of random as to which side will win. There's also a chance one of the factions might get a capital ship, though as far as I've seen, this is just in zones where special story events take place such as in Durius.
