I've been trying to get my daughter to be Alice from Alice in Wonderland for years and finally she succumbed to my wishes! I was a little worried at first that I was going to have to buy a ready made generic costume but luckily on my first thrift store stop with the costume in mind I found the above princess dress!
As you can see, all I had to do was cut off the sleeves (below the elastic) and then cut off some of the length of the skirt and hem. Then I got some cotton muslin and made the apron. Add a black ribbon in the hair, black mary janes and white tights and voila you have Alice!