I'm diggin with what you got to this point, but some suggestions if you don't mind.
1.) The stars seem too stiff and the stroke looks unbalanced, especially with the stars placed all the way in the back. So, how to improve upon this?
a. Foremost, I would reccomend keeping the stroke around the stars the same size no matter the size or distance between them. In order to pull this off, you should either expand your appearance (turning it into a shape) or to go to your transform menu and within the right arrow tab, click on it and activate "scale strokes and effects". This is the better way to go since it won't turn your stroke into a shape, which in result make it impossible to alter, and once you activate it once, it's there for good.
b. Then I would reccomend adding a sense of motion or movement within the stars. This can be a bit difficult since the main focus of this poster is the female figure I am presuming, correct? What I would reccomend is to go under the "warp actions" and alter the shifters under the arc options. See what you get an experiment with others by all means.
c. This is purely optional, but may make a huge impact on your piece. Have you thought of placing the stars behind the female? Again, assuming she is the main focus of your poster, you want your viewers to notice her first. Send your stars to the back or female to the front and see what happens. Maybe if you decide to place them in front, to play with the transparency. Experiment, thats the key thing.
2.) The female's right strap seems to be unrealistic. Makes her appear to have a bazooka sized chest with straps that are about to rip from over-stretching. This could just be a look in which you are going for, but it does stand out as being akward and would normally wrap around the shoulder instead of pulling against it.
Besides that though, it's looking good. The blue shaded backdrop is a nice touch, very easy on the eyes yet catches my attention without missing any of the detail going beyond it.
"You are not special. You are not a beautiful or unique snowflake. You are the same decaying organic matter as everything else." - Tyler Durden