I'd clear up the lines on the girls face, they're currently doing something nasty. The cat and chair look great, and I love the rucked up rug :) Carrolly has a point about oil pastels - nasty messy things. The effect you have right now is more similar to colored pencil work, specifically with the very waxy Prismacolor Pencils (my preference). Personally I'd add a 4th layer in shop - take the full render, desaturate it, beef up the contrast and set that layer to hard light at about 30%. That should get you stronger highlights/shadows which is charctersitic of most handdrawn illos of this type. Nice work :)