If their is a fence jump it. If You can go under sumtin go udner it. If u have to get wet get wet. Just like carrim said the hardest route is the least gaurded. and a lot of times the best route since most people use them almost as if they were walls but if u can get there u can get em in the back.
Oh yeah and don't fire unless u need to. Silence can be your greatest ally then being loud is ur second greatest ally