I decided to use the Oliver + S Playtime Dress pattern. I made a 3T and a 6-12 month size using some of the Cinderberry Stitches Enchant line. My personal favorite is the blue dress.
I followed this tutorial by Jessica of A Little Gray that the Oliver + S blog hosted for the pink version's collar contrast. It was easy to follow and understand, but it came out pretty thick. If I choose to make this version again, I will probably just use a stabilizer for the collar lining or reduce bulk.