The traditional women's skirt-hangers (with the clips) work well (actually, they used to be called kilt-hangers in John Lewis's), but I have always used them in conjunction with the clips Bear uses, which I call "bulldog-clips" available from any good stationery store.

David
P.S. Even those of us with skinny waists (mine is 28") can suffer from "kilt-drop" on certain hangers, hence the bull-dog clips.