There are a few things that I learned which I wish I would have known before I started:
1. Acetate does melt. Hot iron + funny smell = acetate melting!!!
2. You don't need special sewing needles to work with slippery fabrics. It is actually rather forgiving and works with normal needles. I just wasn't sure because knit fabrics need special needles.
3. Most people don't know what horsehair braid is and you will probably have to ask an employee in order to find it ;-)
4. When you insert a zipper, line the dress and proceed to fold the lining under right next to the zipper and whip stitch it down, no matter how neat it looks, those little stitches will get caught in the zipper! Be practical before pretty. Trust me.
5. A formal dress sewn from a wedding dress pattern is really not all that different from sewing a wedding dress. No reason to freak out when people ask you about making wedding dresses ;-)
6. Man made fibers fray pretty bad. Finish everything. It helped that it was lined but I did do some serging.
This is a picture of the "horse hair" braid that was put in the hem of the skirt to make it stand out a bit more. It is nice because it helps the dress float away from the body a bit more but does not add quite as much support as say, a hoop would. This picture is also the best representation of the actual color of the gown also. More warm than royal :)