Hello I'd like to know a critical point about my photographs and how I can improve them.

You won't make money with this. But still, you can improve your pictures a lot, as they are missing dynamic, sharpness and contrast.

You need to increase the contrast of the petal and get that crisp sharp. Take out the disturbing upper left corner and crop your asset, so that less of that background is visible. The branch on the right could also be removed.

The flowers to the left need to have more space and the picture should show more of them(1). If 2 is your main focus poiont, that one needs to be crisp sharp. The foreground does not stand out sufficiently from the background. The contrasts are generally very weak. The whole thing is too soft.

I would suggest doing a search for flower images on Adobe Stock to get a feel for what your competition would be. There are millions on top of millions of flower assets on Adobe Stock, so standing out is difficult.