Material:

2 1/2 Yards Knit fabric

3/8" Knit elastic

Directions:

For the first piece, you want to measure the widest part of your body plus seam allowance. This is your width. Measure from the top of your bust to where you want your dress to fall that is your length.  For the second piece (ruffle) Measure from shoulder to elbow. That is how long your ruffle will be. Measure twice your shoulder area (around shoulder), that will be the ruffle width. Measure and cut the elastic to fit around your shoulder area and one to fit around your top of bust area. 

The hard part is over. Now the sewing. Fold over the body section to allow enough space for your elastic and sew, leaving an opening for the elastic. Do this for the ruffle too. Once done place your elastics in the dress body and the other in the ruffle and close. Align both ruffle and body and sew a zig zag stitch on the front part and back part. These stitches are the only things that should connect the ruffle and the dress. After that, you are done.Remember to hem everything. You should have plenty of room for your arms to wear it as an off shoulder or around the bust area.

Hope this helps. I may have a video for this later. We will see.