The movement and composition are astounding, the negative spaces you've created are beautifully embracing and flowing and the main breaks everything up with so much energy and interest. I love it! I've read about what you mentioned, that the main is unfinished and I think that's what makes it slightly unclear that the weather is "sunny", it could just be that the photograph needed sunlight ( I don't know), but I can tell you that the whites will stand out if the darks are darker, and you can make the blacks have more depth by adding color to them, for example adding red to your black will make it appear darker then regular black, adding green will make it seem a bit closer, you can also use this to warm and cool black areas. There could be an amazing play between orange and blue (overall) when this is finished if you flow a bit of blue shadows into the main to collide with orange highlights from the reddish brown body. And of course it will seem sunnier by using bright highlights in the hair, but the whitest white in the end, you will probably want on that star otherwise the hair could be become overpowering and distracting rather then complementing the overall composition. It would also be nice to see some subtle reflected light, I know the highlights are not in yet, but the shadow from the head gives some hint of where the sunlight is coming from, reflected light often makes things more real then even photographs without it do, it gives things more dimension, and can also be used to bring out the beauty of colors by complementing the main color used in the highlights.

Now I need to go and paint! This is beautiful work!