If that's the sort of thing you're submitting to shutterstock, I can see why you're not getting in. It simply looks unpolished. Visible label on the hammer. The wood is clearly just some random chunk of lumber you had lying around. The "horizon line" is not level, and does not appear to be tilted for any specific reason. The camera position is worth exploring, but I don't think you're hitting the "down low looking up at the descending hammer" visual hard enough.
Stock photo sites have incredibly high standards, because they don't have to accept anything less.
It's all very very clean, very very sleek.
You have a good concept. I was actually a bit surprised to NOT find about a million similar pictures on shutterstock, but if you search for "hammer screw" and click on "relevant" rather than "popular" you'll see a couple things. Look how clean they are, look how dramatic the camera angles.
Caveat: I have never placed an image with a stock company in my life, so, look for yourself and reach your own conclusions.