Inevitabilis

Let me start with the composition. It would have worked well if the lower part switched, then the colors could have worked. I know that you want the two people on the top panel to be together, but what if they were moved to the bottom? Also if the mermaid's face, or Sayaka's face were in close up like the rest of them are, it would also help.

Or, if you do not want Sayaka on close up, you can place her on the middle while she is surrounded with the rest of them. The lower left girl can be positioned at 10 o' clock, Mami at 3 o' clock, and the girl on the upper right at 6 o'clock.

The next one I want to talk about is the anatomy. No matter how people keep reasoning out about it being anime/manga styled, it still looks off. Anatomy is very essential because it helps us relate it to ourselves and to everything. Once you correct your anatomy mistakes it helps you to allow yourself to make more out of it.

+Upper Panel+

For the left, it seems you wanted for her to look up while looking at the left, from afar it looks like she is facing towards us. Position the mouth parallel to the nose, there the chin follows. Remember, the face is not flat, the measurement of what you see at the front of the face is not as the same as the measurement of the head tilting up. The neck isn't that far from the chin. And remember, our shoulders are not exactly straight.

For the right side, it seems that you intended her to look upward. The only problems are the mouth and nose. The mouth does not appear like that in that angle since she is just facing slightly to the right, in her perspective. A helpful suggestion I would like to give you is to move the mouth upward, or nudge the nose slightly to the right and nudge it way down; place it between the distance of the nose and mouth.

-Lower Panel-

Sayaka left eye (or right eye from her perspective) is positioned too high, nudge it down parallel to the other eye. And yes, the eyes are not that far apart for it to be like that. Nudge the nose a little bit downward. Or a different solution for you is to move the mouth and the chin to the left.

On the right side, the chin is off; it is not angled like that. Or else people will be having a hard time chewing food. The eyes are fine, but moving it very slightly forward can help. The hands and the body are tiny for her head. If you disagree, compare Sayaka's body and the rest to her body.

Next are the colors, all of them has harmony, but for each of its own. They would go well on their own alone.

The lighting was the best on the lower right corner, but the lighting was uneven for the whole composition, as if they were separate images. I think this is the reason why the whole picture does not look harmonious. The thing I would like to recommend you is to have a same light source for everyone. For example, the light source can be at the middle.

The textures, they look good but there were a lot of effects that were not necessary or did not work well. Like the red cloud fog and the mouth shape for Mami. The overall four did not combine well. Perhaps separating them all with the ribbon can help.

The other compliments such as the tea cup, spoons and fork could have been better if they were bigger. And the cross seems out from the picture, perhaps moving it behind her back can help.

For the whole picture I think you need to consider the characters as a whole, not as individuals. The image might be about discord but I don't mean to be rude, but it is not appealing. Individuality yes but everything is heterogeneous

Overall I did not critique to discourage you but rather to point out the things that do not work well and help you improve. People might think I am not in the position to critique based on what I make, but in my opinion my judgement has its points that can be helpful for you.

Thank you for reading o/