I followed these directions of how to piece the dress together, but I made mine differently since I used left over fabric that I had lying around the house. If you want to do what I did, just take the fabric and fold it in half. Take a dress that is about the size you want to make yours and cut around it keeping a 1/4 in around to sew it together. Or cut a rectangle of the size you want your dress and cut out arm holes and a neck line, then sew them together. (In a later post I'll have a tutorial that will show how to do this for a better visual)
Of course I also had to make a headband to go with her dress. As I was looking for tutorials, I stumbled across this website and instantly fell in love Snazzie Drawers. The best thing about it is that she sells her patterns! And if you don't want to make your own, she has her own etsy store. I used her headbands as my inspiration (I just copied hers). (To make the flowers for both the dress and headband, you can use this tutorial.)
For my son, I really wanted to make him a suit, but alas, I ran out of time (hopefully, that will be a later post). I did, however, make him a bow tie. I wanted it to match Chloe's dress a little, so used the same blue fabric as her flowers. Also, to make this A LOT easier, I used a white elastic for the band, so he can put it on or take it off himself. He loves his bow tie, but didn't let me take a picture of him wearing it.