I started with a pattern I had downloaded - "Kate's Dress" by Lily Bird Studios. I purchased it here: http://www.etsy.com/shop/TheLilyBirdStudio#.
I had no idea how the sizing ran, so I made a size three for my tall-ish 2 year old - who will be 2.5 in about three weeks. The dress went together without a hitch. Although I've been sewing for a bazillion years, this was my first time with piping. I put my zipper foot on my machine, and was pleased at how it came out. I used the string that we use to tie up poultry inside the piping - no idea what other people do, but it worked just fine. In retrospect, since I've never used piping before, I'm sure it would have come out better if I had used the other view included with the pattern, which has a much larger rounded yoke, with no corners to try to turn.
The sleeves are absolutely adorable to me, which is why I think a ruffle at the bottom may just make this the perfect, totally easy dress!