After making the turq/ choc batik dress and big girly flower dress, I am officially in love with the pattern so I'll probably make 100 more! A couple of people have asked how to do it, so I took some pics as I went along.
Here's two I made last night:


And here's how! Firstly, I'm heavily indebted to vegbee for a peasant dress assembly and she's much better at explaining things (and making them!!) so I'll just skim over those bits. It's in the tute list if you don't know what I'm on about.
Start with a peasant dress shape (bodice, sleeves, sleeve cut away). I wanted a two inch band at the neck so I drew a line 2" from the top on each piece.

Fold down and trace a new pattern, this is what you will cut the dress based on.
Cut bodice, sleeves, armholes. Assemble as per vegbee's wonderful tute so you end up with this:

Lay the dress out with straight line across top, measure. Make another pattern piece of width + small seam allowance x 4" height (double the 2" band that you took off the top of the original pattern).

Cut on fold. Right sides in, sew ends together.

Match edges and fold band in half widthways so right sides are out, iron.

Now you make the two channels for the elastics to go through. (You could wait and do elastic channels once band is sewn to top of dress, either way works just fine!). Do first one quite close to top, I line up edge of foot with edge of fabric. Sew all the way around the band, leaving it open about 2 inches at the band's seam (Wide enough to get your fingers up in there).

Sew all the way around again for the second channel about an inch from the bottom, leaving about two inches open again. Then pin to the dress, matching up all the raw edges and placing the part of the band with the seam at center back. It'll look like this:

Serge all the way round except for that same two inches open in the back. Like so:

There are now two channels for elastic. Cut 2 pieces of elastic to fit child's neckline, the upper one should be about 4 inches shorter than the lower one (or else it looks like a turtleneck!). 14" and 18" seems to work for my little girl. Sticking your fingers up the handy hole in the band, run the elastic through top casing and secure, and then bottom elastic and secure. Close the 2" gaps for both the channels and then flip back down and serge shut the 2" gap where the band attaches to dress. You're done!
Clear as mud, right?!