A sleeveless circle(I would recommend 3/4) dress pattern would work well. I would also recommend having a petticoat under to make it more puffy. To make this dress you can find a pattern that looks similar [IMG]like this[/IMG] or this
and alter it, or just make a bodice and attach it to a circle skirt. The collar can be attached to the dress or make it a detachable one. While making the skirt, make sure to look at the reference photo to see which fabric should go at what part.
Use light white fabric (cotton) to make the ruffled part. The whole dress would look nice in bridal
satin (please don't use normal satin), but you can use matte fabric too
I hope that this was a little helpful to you