Personally, I feel the concept is kitsch, to put it mildly. However, if that's what the client wants, they're paying the bill, so....
I agree with the comments previously posted. I would also add:
The softbox reflected in the bottle looks wrong, as does the aforementioned tungsten light added on the right side of the image and the other misc. reflections make the bottle look cluttered. It's generally considered a good idea to use a silver reflector behind the bottle (carefully trimmed to match the shape of the bottle from the camera viewpoint) to add some sparkle and color to the wine in the bottle. I use silver mylar drymounted to mat board, you could just as easily spray glue some aluminium foil to some mat board scraps.
The lack of a highlight to define the shape of the bottle makes the shape vague. Well done low key glass shots work well, but need a stronger composition to pull it off. I would add that if you want to shoot glassware and bottles, you really need to get a copy of "Light, Science & Magic" by Fil Hunter. Specifically, the section on dark field photography is apropos here.
Learn how to use reflectors and flags, they'll allow you to place your highlights, birng your shadows up in value a bit (four color offset printing can only reproduce 4-5 stops of information, if everything is dead on and perfect, so a lower contrast image will look better in print.
The bottle should be rotated clockwise, you don't want to show the surgeon generals warning, but instead emphasize the label.
The composition is too static, with nothing to lead the eye to any focal point, an asymmetrical composition with a leading line of grapes would work better. Having the bottle dead center doesn't allow you room for your copy, and relegates the image to a "pretty background". By using an asymmetrical composition, you allow yourself room for your copy, and with good typography, make the bottle the focal point of the ad. BTW, other than it's what you had on hand, is there any reason why you have both white and red grapes?
On the subject of grapes, I'll give you some advice. First, buy some florists foam at a hobby store and spray it with Krylon ultraflat black. Then carefully remove every grape from the bunch (you'll need about 2 to 3x what you'll end up with). Throw away any that have any defect whatsoever (or better yet, put them in a collander, rinse them and snack on them for the next couple of hours while you polish grapes. After all the bad grapes have been weeded out, take a cloth moistened with vegetable oil and wipe each grape down, followed by a dry cloth to polish them. When your done with that, get some black toothpicks at a part supply store. Finally, clean the ends of the bunch stem, leaving it clean. A quick few coats of Krylon matte finish and let it dry. Now start to build your bunches on set, using the black foam to support the stem, and the toothpicks as needed to position the grapes realistically into bunches. The idea is to have cascading bunches of absolutely perfect grapes. After you're satisfied, take a spray bottle with a mix of distilled water and glycerin and lightly spray the grapes, if you want a droplet at just the right place, use an eyedropper, or tweezers to place. It's a lot of work, but the results will speak for themselves.
Unless you're printing an odd shaped poster, the proportions are wrong, you want to work closer to the aspect ratio of 4x5, or so. Specifically, for a full page ad, you want an image that is 8 3/4 x 11 1/14 (full page + 1/8" bleed) for a full page full bleed ad. While it's hard to conceptualize, after a while (or a couple decades, in my case), you "see" in that aspect ratio.
Low key can work, and quite well, but you need to have a strong composition, good knowledge of lighting, and the ability to use light to shape the product. It's a good college try, but quite frankly, you've got a ways to go before I'd even consider it a finished product. One thing I'd suggest is a trip to Joann's or your local fabric store to buy a yard or two of Black Velvet (fabric, not the whisky...) It's expensive, but take care of it and it will last for years.
I want to thank you, you've helped me to avoid some work I really don't want to do right now for an hour or so, and I hope some of what I've offered can be of use.
erie