I made this dress for my daughter last night, and I just love it! I went ahead and took pictures as I went, just in case it turned out well, and I think it did!
Here is the finished product:
When you're done sewing the sides together, thread the left shoulder strap through the left sleeve, with right sides facing each other.
*Note: I sewed my dress with the sleeve seams purposely facing outward. If you prefer to go with the traditional seam, you'll want your garments to be right sides in, with wrong sides facing each other.
Throw a ribbon or belt around it, and your done! I actually added a skinny elastic to the inside of the waist of mine also by simply pinning it in place, and sewing it on while stretching to to fit the fabric. If you'd like a short-sleeved version, simply shorten the length of the sleeve on the unfinished side, and sew as usual.
I think I should add that this is my very first attempt at sleeves! It wasn't nearly as difficult as I imagined. I'm not sure if I did it the easiest way, but it worked!