Frame one: the prow
Shoot from the north first. This is the image most people came for, and it shows why the building has been compared to a ship moving through the avenue.
Frame two: the city around it
Step back. Add Madison Square, traffic, trees, or pedestrians. The Flatiron is not a standalone sculpture; its meaning comes from the grid break around it.
Frame three: the surface
Finish with ornament. Masks, cornices, windows, and facade rhythm make the building more than its triangular meme.
Image: chrisinphilly5448, Public Domain Mark, Wikimedia Commons