I herd a lot of ppls complaining about blender cloth simulation for characters. Yet the tutorials that we have are with balls with simple cloth falling on them. There is a few with characters but they always have problems and wonder why, yet everyone follows that tutorial to end up with the same problem those tutorials had. Well, here is the right way to do it. The real trick is to NOT use an armature modifier on the cloths, simply cause it causes double modifications which causes numerous cloth calculation issues. Instead, parent the cloth on the most appropriate bone on the character rig, and let the simulation do the rest. And you’ll end up with results like this 
Here is a second try to get better results and less jiggly cloth!
I hope this helps many 
Happy Blending