I grew up in a city of about 50,000-I knew my way around primarily by landmarks. As JB states above me, my directions always revolve around major landmarks that may have ceased to exist years ago. Funny thing is, people who are recent residents will still give directions using the same formula...likely repeating what they were told!
That's when I knew I was a "local" and no longer a Manhattan resident at heart.
I was asked to give directions to a place. The person was a "recent" resident - maybe a year in the area. Here is exactly what I told them:
"You go up the hill, past the the place that has the sheep sometimes, and then keep going until you're about a quarter mile before where the burned out trailer used to be, and then turn left there on the lane. There's no sign on the lane, so be careful."
The look on his face was great.