Here are a couple of very different approaches to fishing down a wall.
The first is
NORCAL's flex tool. It''s made for pulling flex down a wall with a fishtape. The angled end will take the flex smoothly with it. Finesse
The other is my "Wallbomb". No finesse here. You could tie your mother-in-law to this and drop her down the wall with ease.
Anybody else have any little "gizmos" they'd like to share???