Raro, I've discussed negotiations in this thread as well in saying that there's luck in the sense of encountering the right attitude when conducting negotiations. The language arts you use will influence different attitudes differently. If you encounter incompatible attitudes right away, your negotiations will fail.
I agree that overall strategies matter as well, but when it comes to multiple rational players playing against each other, guessing the right tactic ultimately comes down to the circle of, "If I do this, he'll do that, but if he does that, then I ought to do the other thing, but if I do the other thing, then he'll do this, so if he does this, I ought to do that."
Ultimately, you have to randomize your tactics to get around the circle.