I added some side darts to the bodice and made a tuck on each side of the neckline, which I have just stitched as darts for now to get the idea. I then turned under and stitched down the seam allowance along the neckline (in the actual dress, the edges are finished by a facing piece that is sewn like a lining). I threw a couple of hooks on the back so I could get it to stay on. I think the fit is much better now. I might also add a little more length to the shoulder seams so my bra straps don't show.
I'm sorry this picture is so blurry, but it's the best I could get by myself. You can kind of see the tucks I made at the neckline near the center front. (Any advice on how to alter the pattern for this?)
Here are the two fabrics I'm thinking about. The top one is a cotton voile with a black background; the bottom a black woven polyester. The coin on the black fabric is a quarter.