The belt prevents the skirt from falling off.I sketched some models on it, but not too many because the skirt is already very detailed.
The skirt may look complex but it's not. There are great tutorials on DragoArt on how to draw folds, so I'm not going to show that again, but I do recommend to start with the outline and then to define the folds. It is easier this way. It has a lot of layers, but don't overdo it. The skirt goes on the same principle, but do keep in mind that it is not made of a delicate material. It's similar to the one wich ballerinas wear.