You've got some very interesting characters. I like how you add a lot of variation to them, and have different types of clothing.
I'm just going to suggest a few things for the colored give art. I think her clothing would look a lot more 3D if you added some folds and had her skirt flair out a bit more. Find some other images with dresses and see if you can mimic the flow of the fabric, then change it for your own image. Also, her left hand, our left, is not defined very well, and I think a little misshapen (sorry I couldn't find a more tactful way of putting that.) It would also be helpful to study the anatomy of a hand, and understand how the parts work underneath so you can make them look more realistic. I have trouble with hands, too--I'm still not all that great, and need practice myself
Her body seems a little long, the torso area. I would point out the belly button...but if she's an angel, I'm assuming you left that out on purpose?
I love the green and black/yellow and black color combo on her dress. I also really like the design of it--it just needs a few more details, and I think it'll look even better :3