How do you attractively drape an afghan?

I've tried draping an afghan or throw over the arm or the back of a sofa... but it always ends up looking clunky, not draping elegantly like in a magazine photo, and then I just fold it and put it over the back.

Does anyone have a tip for doing this? I realize it's easier with a lightweight throw than with my Grandma's warm wool afghan that I got out this morning, but I can't even get a lightweight one to drape "nicely."

Thanks!