The usual poly/elastene that even when dumped on the floor looks like a dishrag. Going back to the style, the American designers, unless its a maxi dress, never seem to get the length right for the UK market. They are obsessed with a short hem. I used to love Ronni Nicole, but those dresses too were far too short for my 5'7 height. Ok if you want to show off the pins, but most of us at a certain age who would buy the range, do not.
These American designers need to do their homework more, because the amount of Clearance fashion should given them an indication that they are getting it wrong somewhere. I would suggest a) ditch the poly/elastene b) ditch the god awful stretch cover prints c) be more aware of the hem length.