It can be annoying when your clothes constantly fall off their hangers, especially after you have folded and washed them. However, there's a pretty simple method for ensuring that things like pants and dresses stay on their hangers. For pants, just take one of the legs and put it through the hole in the hanger. Then, just fold the other leg over the one already through the hole, and they should stay on.
If you're trying to hang a dress, then just fold the corners of your dress inward and then put the hanger around either the bottom or top third of your dress and pull it through.