I'm by no means an expert, I've only started out recently as well.
To me both these photos look to have some exposure issues: with the flower the petals look overexposed, the fine details seem to be lost in the whiteness. Also on this same picture the blurred background seem to have some noise in it, which probably is due to high ISO setting or some post production compression issues. The beach on the other hand looks a bit underexposed, especially in the left upper corner, maybe you had some shade in the lens or something.
Don't get discouraged, in the beginning you'll have a lot of rejections, but sooner or later you'll improve your shooting and post production techniques and will get accepted 🙂
As mentioned by @Sink Ink, there are exposure and noise issues.
The flower is not sharp at all.
The second one isn't particularly sharp either, but the exposure (overblown highlights and very dark areas) and colors are clearly what catches the eyes at very first look.
To me, just taking this small area as example, the satured blue and exposure from very dark to white are clear signs of extreme overediting.
Hope that helps,
Michael Niessen - Photographer, photo-editor, educator
The bloom: the lights are blown out and the shadows underexposed. Why did you increase the whites while editing? It looks like you've painted in black with a brush. The flower is poorly focused and there is color noise in the picture.
The beach: The lights are blown out and the shadows are underexposed. I am irritated that the focus is on the ball and not on the woman. The black spot on the top left is annoying.
Post processing seems to be your main problem.
Thank you for your message.
Indeed, post processing is new to me, I try not to abuse it 🙂
It's funny, because I tried to highlight the woman and not the ball ...
I do not give up