Pretty good
I'm just gonna hit the flaws: the hair that's over-head looks too stuck to her face; it's not out there enough. Her forehead is gigantic, but that could be the real thing. The eyes and eyebrows are too far apart and the eyeliner/eyelashes/whatever that is looks incomplete and messy. The lips look like hooker lips and not very angle-correct. Her left (our right) nostril is pushed back because you drew her finger in front of it, but it's not actually touching. Also, there's a line there and the hole is too big. The forearm up front is too wide and muscular-looking compared to the rest of her, especially the arm itself. The straps throughout aren't at the realism level like the rest of the drawing; they look simple. The layering of her right (our left) arm and the torso is confusing. If the torso is in front, you should've made it wider or the arm thinner. The line between that arm and forearm is too defined and stretches across the whole thing. The shadow being cast from her hair under her neck looks like some folds rather than a shadow. Speaking of which, the folds of her armpits are too defined, as well. There's something about her jaw and chin that I don't like. The hairline isn't detailed enough. I suppose the (whatever that outfit is called) ought to have some detail and shading, but whatever.
Well, the positives are that it looks overall good and the value around her actual body is great. Good positioning of everything.
...... wait, this is supposed to be Scarlett Johansson? ...hmmm, it doesn't look like her at all.
Well, you've got the potential. Just look over the little details here and there when you're drawing and you should do fine.