I made this tier dress using a vintage McCalls tank top pattern. I did make some adaptations the tank's top and obviously turned it into a dress.
Cutting the bottom edge of the upper portion of my dress was done using the tank top pattern specification. I simply moved the pattern down, realigned it 1/2 inch from the center fold, and cut the bottom using the arc provided by the pattern. I repeated this same method for the back of the dress.
I sewed the top portion of the dress before attempting to cut the bottom tiers. Once the upper dress was sewn, I measured the width of the bottom edge. I cut my bottom tiers 13 inches wider than the dress width. If I had to do this again, I would cut the tiers about 18 to 20 inches wider than the width of the dress.
For the tiers, I approached each tier differently. The bottom tier was cut at 6 x 40 inches and the top (outer) tier was cut at 3 x 40 inches. Both tiers were cut in two pieces and sewn together at the sides. From this point, I approached each tier differently.
The outer tier was given a rolled hem on top and bottom, using my overlock machine. The top edge was given an extreme lettuce edge effect and the bottom hem, a mild lettuce edge effect. Once my top tier was hemmed, I used a single need straight stitch, on stitch width setting 5, to gather the top edge of the outer tier (approximately 3/4 of an inch from the tip of top hem). After gathering the top edge of the top tier, I pinned the gathered top to the seam where the bottom tier was attached to the top of the dress. I used the gathering thread as my guide for pinning and sewing the outer tier to seam joining the bottom tier and upper dress.
I used a cover stitch machine to attach the outer tier to the dress. Once I completed the outer tier, I removed the gathering thread.