I am working on a wuxia in RPGs article for theRPGsite so today is going to be brief entry as that is taking up much of my extra time. Last night I was thinking about what trips me up most as a GM. I think the thing that disrupts my performance the most isn't players avoiding things I might have planned for, it is when they approach the things I have planned from a completely unexpected angle. I've found the best reaction to is be adaptive, shake some of the prep from your mind and allow things to move organically.
I like to go into a game session with a strategy, having actual notes and material on hand, but also having a game plan for things that are likely to come up. For example, in my Wandering Heroes of Ogre Gate session I knew that one of my NPCs would be looking to discuss some concerns about the Sect alliances and about his daughter marrying one of the PCs. So I had a simple not to this effect on a bullet pointed list, among other such reminders for different characters and events, to consult and keep in mind during play. Personally I just find that sort of thing useful, in case I grow a little forgetful. But the problem with it, is my mind can get too focused on what I have written, and forget all of the unwritten possibilities.
I look at it a bit like an athlete going into an event. You have a game plan, you have some notion of what you'll do should X,Y or Z occur, but those are just hypotheticals, once you are in the moment, you have to deal with whatever is in front of you, and make the best choice for that moment.
It is just like that when you are GMing. You can explore the hypotheticals before the game, you can plan some notes and have an idea where things are going, but if you don't see the possibilities as things are unfolding because you are thinking about what you had planned, you miss out.
So let things unfold. Allow the dice to tumble as they will and an interesting campaign will emerge.