I think I'll probably end up making a better one of these later on, but here's a quickie version of my first attempt. If you've got a better idea for how to do a step or describe it, feel free to tell me. I know this one's not perfect.

Start with the Jayme bodice pattern. You'll need two of it cut from fabric A and two from pattern B. You will also need to make two straps and 4 side ties. I made my side ties 16" so I could tie a bow, but I think they are a little full and will probably make them shorter next time. I made my straps about 9.5" since I guessed I wanted 8.5 finished because it's for girl who wears about a 7. I probably should have made it to fit one of my boys' sizes, but they can't wear it and weren't awake when I started.

You'll also need two skirt pieces from each fabric. I made mine 12" long and half the width of a standard woven to get the best fabric use. You can always cut out the bodice and then measure the child to get a good length for the size you want. I rounded off the bottom corners using one of my salad plates as a template.



Next, sew the side ties and the straps onto one of the bodice pieces from Fabric A using a really scant seam so this will be hidden in your final seam allowance. Sew the second pair of side ties onto the second Fabric A bodice.



Gather the top of the skirt and attach it to a matching bodice. Do this for all four skirt/bodice sets.



Press the seam towards the bodice and top stitch.



Match up a fabric A with the straps and fabric B set. Sew them together right sides together leaving a 4" opening along one of the skirt edges. Sew using your seam allowance, making sure that all straps and side ties are inside. Turn right side out. Press. Topstitch.



Match the remaining pair of pieces right sides together. This time, leave the top edge open. Sew around the rest. Turn. Press. Fold down the top edge and insert the straps making sure to measure so that the straps will be even. Pin carefully, then topstitch the whole piece.



You're finished!

Here's how it looks on my 2/3T model. Definitely too big, but probably workable as a dress with shorter straps:



Here's how it looks on my 5T model. I still think the straps are too long.



Finally, here's a couple of non-modeled shots.