To be honest, the only issues that I see, and I am partialy guessing, are depth of field is too shallow and some of the highlights are blown out. By that I mean not enough is in focus and the white spots, sunlit spots are too white.
You have not achieved sharp focus in any of these images. Perhaps your shutter speed is too slow, or the flowers are moving in the breeze, or you didn't hold steady enough. While capturing flowers is a good way to practice your photography and editing skills, Adobe stock is already saturated with millions of excellent floral images. Getting any accepted or ever sold is a long shot...
Digital photos are rarely perfect. They all require some adjustment in Photoshop or Lightroom.
But as @Jill_C said, this is a fiercely competitive category with little sales potential. Find other subject to photograph. Anything but flowers, leaves, trees, sunsets, clouds & pets. Preferably some real life situations with people who will sign model releases. Or interesting objects that tell a story. The best Stock images invite viewers into the scene.
For more tips, see links below:
Better luck next time.
Thanks all! I am just dipping my foot into this. I will work on branching out to some other avenues in the future. Luckily I have 4 photographic adult children so once they are home from college I will see if I can get them to go on a shoot with me. Thanks again for your critiques, I have been doing mainly sports photography locally and now that my kid's have graduated, hope to branch out a bit on a part time basis.
5180: not in focus, noisy. I also suppose that you did not submit here the full-size image. You absolutely need to lower the ISO. ISO 3200 with an exposure at 1/1250s exposure time on a non-moving asset is simply overkill. You can lower your exposure time to 1/100s and avoiding high ISO. It will give you a sharper image and less noise to compensate.
Applying a small punch to the colours and adding some contrast gets a more pleasant image:
The image is technically not underexposed, but the flower is a little flat and light.
5166: Out of focus, flower pictures need rigorously the hearth of the flower to be in focus. ISO too high, so you still have a lot of noise. It's slightly underexposed:
(to the right of the histogram, whites are missing). You could also add a small amount of vibrancy to this image.
5400: That's a nice picture and a near miss with the focus. Either you need to improve focussing accuracy or you have to close the lens a stop or two, depending on the lens's ability to produce sharp images. It's ISO 100 and you see immediately that noise is quasi absent.
5408: focussing. Same advices as with 5400.
5200: a big miss in focus (seen here at 100%):
There is also some noise, I think that you tried sharpening and noise reduction.
@Jill_C did not look into your EXIF data. As what she says is correct in general, your focussing problem here comes from your lenses and the wide open setting in some images. High ISO creates even with the most expensive camera/lens combinations softer images. You should always keep your ISO as low as possible. As you set your camera mostly in manual mode, I suppose that you also shoot raw. If not, try that out. It's worth to recover more in your pictures than the standard in-camera processing.
Your pictures are nice and will get accepted if focussed correctly, but you should know that flower pictures are not getting you rich on stock. I wouldn't shoot flowers for stock, but I have uploaded flower pictures myself, and they sell…on the low end.