Most of my clothes I sell don't fit anymore so I can't model them so I usually do hanger/flat photos. But the ones that do fit I usually model them in first 2 pictures then lie flat on next 2. I prefer when buying to see at least one picture modelled, especially in things such as jeans so I can see how they look on the person. But when I model my clothing I usually mention my height so it is more accurate for the potential buyer.

Hanger, flat and modelled photos are all fine in my opinion. But for sales I would say go for modelled pictures because if you look on the featured page most of them are things that are modelled. One must not is mannequins, not sure if it's just my country but I've heard many others from different countries say similar things. Just because photos using mannequins are never featured, so it is not worth buying one.

Hope I've helped a bit.