Good compositions, but one of these days you're going to have to learn not to lose your shadows and your highlights to all buggery.
Shall we demonstrate?
Number 1 has her hair fading into each part. It doesn't take much PP work to bring that out. I'm going to assume you don't know how or that you're not very good at post but all it takes is a bit of patience, feathering, and curves Dan.
Number 2... there go those highlights again. I can assume her right breast (left to us) isn't supposed to be radiating light?
Number 3... so her black bra is made out of the darkest, most evil, and stealthiest technology known to man kind... not if you look at the straps it ain't.
Number 4 is your best. I have nothing to say about it colour wise, but I'd stop making your
models lose so much skin composition. They seem plasticy.