Looking out the window
You have to look out the window over there. Just following the GPS often does not work.
I remember, a Long time ago, flying a tripacer through the Haast pass underneath solid cloud. Fortunately we had talked to the local aviators before we did it, and they were greatly amused when they saw the straight line we had drawn on our WAC chart. (that's what they teach you at flying schools.)
To see some real bush flying I can recommend the video's "The venison hunters" and "the last great adventure" by videosouth.