Can someone please tell me where I'm going wrong with my mesh?

Sorry if I'm posting in the wrong place... Or if no one here meshes.

I don't know anything about meshing, however, I did find this, if it helps at all.

http://sims4studio.com/thread/4324/tutorial-detailed-guide-create-clothing

Thank you. I've used this tutorial before but couldn't follow because I was still super new to meshing and using the necessary programs. Looking at it now though, since I've learned a bit more, I think I might be able to work with it. 

Are the weights assigned properly to the mesh? If you don't get what I mean there is a thread on the sims4studio forum to help.