There are certain clothes that just don't seem to want to hang on wooden clothes hangers, but if you don't want to replace every hanger in your closet, Instuctable user bigbang has a simple tape wrapping trick to keep clothes from falling.
They recommend using hockey tape, but any thick tape should do the trick. The wrapping method creates a makeshift shelf and keeps clothes from sliding off. If you happen to have an abundance of vests, big sweaters or v-necks, this should keep them from finding their way to the floor. Head over to Instructables for a full how-to on keeping the wrapping clean and neat.
Hockey tape clothes hanger grips [Instructables]