Don't just fight in the North or the South. Always imagine every battle in your mind, where everyone is both your enemy and your friend, and all possible events happen simultaneously. That way, nothing will take you by surprise, and everything that happens will be something you've already imagined.
My mind is my weapon. My brother has his sword, King Robert has his warhammer, and I have my mind... And a mind needs books as a sword needs a whetstone, if it is to keep its edge.