I started by gathering several different inspiration images of hime lolita fashion. In a nutshell, hime fashion focuses on big hair, lots of ruffles and crowns - merging lolita fashion with what you would imagine is a typical princess outfit. For a more in-depth explanation of hime lolita, check out this link on HelloLace.
Below are my initial sketches. I like to start by drawing out the body, unclothed, in red prismacolor pencil to make sure all my anatomy is correct before overlaying the clothes. For this one I paid special attention to the hands, as they will be the focal point of the piece.
initial anatomy layout
refining details and starting to plot out the dress