If you sew two lines of sewing along the top (keep the lines straight without crossing over each other) you can then slide the tulle along to make the top smaller than the bottom. (can't think of any of the right words, but equivalent of lots of little pleats)
You don't want a cut edge to be where it will touch your skin cos it can get itchy.
you will need to do as the other poster has said.
my other trick is to not cut to exact length untill you have finished sewing it.
also you want to wash in vinegar before hand to help soften teh tule it makes it easier to work with. and maybe need to tack some layers together from underneath so sewing upwards at all times. this will help lift teh skirt and not make it flop to flat
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