I cut the fabric 44" x 56" and ironed and sewed the 2 edges that weren't already "finished".
Next I folded it in to fourths, and measure for the neck. I used the measurements of my pink one to eye ball it - but I made it a little less "plunging" in the front as I didn't want to always worry about the girls showing :).
I laid the material out with the opening facing up, cut 3/4" on each "corner", then folded them down twice making the hem. I am sure there was a better way of doing this, but this is what made sense to me. Once I was finished sewing it all the way around, I moved on to the next step.