Fishnets are great for either adding texture and depth, subtly subverting a conservative look, or both.
-tweed pencil skirts /twin sets and pearls.
-when layering a variety of prints or textures in similar colors
-adding interest to shoes: patent mary-janes for a dancerly look, or adding depth to strappy heels
I have them in black, chocolate, nude, and also a fuschia/black mix which goes especially well with vintage print dresses from the 60's and 70's.