I found an old onesie I had laying around (9 month size) and cut the bottom off of it.
Next, I cut two rectangles from the knit fabric, they measured about 3 inches wider than the width of the onesie. I sewed the two triangles together, front to front, creating a tube.
Then I sewed the "tube" to the oneside and hemmed the bottom.
For the "necklace" I ironed on some heat n bond to a piece of the knit fabric and then cut out the circles. Then I removed the backing and ironed them onto the top of the onesie. Finally, I sewed through the middle of each circle with a decorative stitch.
Now Miss Charlotte has a dress that was made just for her :)