Looking for advice

Shoot more. You've got an attractive subject, and whether on purpose, or by accident, you seem to be doing well already. By using your longer lens zoomed in a bit, and almost wide open, you've isolated your subject from the background. Looks like her hair is a bit backlit, and you chose a location/time with soft and flattering lighting.

You could work on your composition a bit, as I would like to see either more of her figure, or zoom in more on her. And the jacket is covering her up, but it gives her a sense of modesty. She's hiding her sexiness, but you know it's there. One minor detail is the hair by her eye - that's no so good. But the splash of red on her lips draws the eye to her face.

Your depth of field was not as shallow as you wanted, so you tried to fix it in post. Good attempt but quite tricky. Better done in camera, if you have the lenses for the depth you like. If not, you are going to have to use longer lenses and or shorter distances than you might have chosen.

What do I like? The subject is pretty and seems to have a nice facial expression, looking at us. The setting is OK, the lighting effect does not look real but if it did it would have been OK/quite good even.

What do I not like? Her behind is too prominent, pin sharp and bright blue in a shot of almost entirely muted monochrome colours apart from the very small area of red lipstick, for a portrait, in my view. A backside should not be more emphasised than a face in a portrait, makes sense to me.

I don't like bits of underwear to be into portraits, even a bit of bra strap appearing at a neckline. Here, half the bra seems to have been "accidentally" not covered up. I use that wording very carefully. The wardrobe choices here seem non existant for a portrait. Don't misunderstand, I have no problem with lingerie or nudity but this is presented as a portrait and the bra back showing above the back of the top she is wearing is all a bit messy/distractng. In a portrait we need to focus on her, not the casually just happened to be in my clothes that don't work together look. The coat would have been better on the far shoulder, or worn, or gone.

I would have cropped tighter and perhaps added a vigniette.

Stick at it. If really good photography of any kind were easy it would be boring to do. After 41 years I can tell you that hand on heart, and as long as you continue to care about photography you will keep learning about it. I do every day.

Good attempt Devyn. My advice - listen to Ian. I've seen many of his comments here, and he knows what he's talking about with years of experience behind him. Both he and "prefers" have given you good advice that I really can't add to accept to say have fun with it. You really do appear to be off to a good start. Good luck!

I think you did a decent job. I like her post and the light in her beautiful hair! One thing that I did notice is that there was some post production blur to create more of a depth of field...however it is noticeable (you can see the around her body ) I think the photo was probably ok without the added blur.. I am a fan of a nice creamy background myself but if you don;t do it in camera then my advice would be that you need to be very precise in post so that it doesn't look fake or sloppy.. that in my opinion can kill a great image. Also this would be a really nice tight crop sort of stopping at the bottom of her hair. Looking forward to seeing more of your photos!