Disclaimer on the star rating: The rating is completely arbitrary and in no way representative of how I feel about this piece. I'm writing this to provide feedback, not to rate if a piece is hot or not based on some vague criteria.

That said, what I find really strong about this pieces is the color scheme and the use of contrast. The fact that you only used orange tones contrasting against black really pulls the piece together, and the colors just mesh really well together.

Shadows:
The source image you picked has fairly even light, but also some really nicely defined 'lines' so to speak where seperate body parts touch, for instance her left arm against her upper body, her bent right arm, and her legs, and I feel that those lines are really important in order to distinguish between those shapes and shouldn't be left out. Even if you want to make stark black shadows, you could make those lines white so things don't turn into one massive black shape. Maybe I'm doing a bit of a poor job explaining what I mean, but you already did this with the line that seperates her right and left leg.
Some of the shadows just look weird: Her left arm has these weird folds that make it look like she's wearing a sleeve, even though her arms have smooth skin. Her legs also have a jagged shadow that doesn't look natural. I would also recommend that you remove the small lines at her feet, because the tiny detailed shadows feel out of place in a piece that largely defines itself through rough shapes and stark contrast.

Hair:
I think this is one of the areas where you would actually want slightly *more* detail. You only drew one "big" curl in this piece where the model has about four, and you neglected all the small curls except the ones at the bottom. I do think that the top and bottom of her hair looks fine as it is right now, it's really just the left side that needs some more love.

Composition:
I see several things going on in this piece that don't serve the model well. There are two really dominating visual elements: The first one is the orange curve, and the second one is the black shape to the left, which draws the eye towards itself and away from the model, who is located on the other side of the picture.
The orange shape gives the piece "flow" and leads the eye from the top left to the bottom right of the picture. The problem is however that it doesn't lead towards the model, but below, and outside the frame. The fact that the model is partially out of frame herself doesn't really help, either.
Here are some examples of lines serving the composition, by leading to the most imporant subject of the piece: [link] (it's photography, but the principle still applies). None of the lines in the examples given lead outside the frame, and the most important subject matters are neatly placed according to the rule of thirds. If you apply that rule to this piece however, all the points are empty except for the bottom left one, which is located point-blank at the base of the orange curve.