1080p; Rendered with 1024 samples, then de-noised using a custom method:
difference of Gaussians for edge detection, then Despeckle to separate noise from edges, then dilate and use as a factor for mix with an image-informed bilateral blur.
I took direct glossy and excluded it from the de-noising to retain sharp detail.
The sushi uses a simplified glass shader (refraction and glossy), with procedural textured volume for the fish. The rice is a SSS-shaded particle system with transparent shadows, and I added real displacement and a sharp glossy sauce “brushed” on top.
More light, hdri seems fine just stronger.
On fish, less glass more translucency, and also it’s too smooth, needs some fine muscle bump.
If it’s salmon (my favorite) color more saturated, brighter and closer to orange.
overall shape of the rice is too rectangular, should be rounder squished a little, also rice needs more sss/translucency and gloss.
less DOF, and if you’re using an aberration filter kill that.
The fish is salmon… So, you got the material colors wrong, it needs to be more orange. Try to look at reference photos and match the color. The fish part is nice, but too rigid. It needs to feel softer, again, refer to reference images to see what you need to change. As for the rice, I feel that it’s dry, so make it look wet which obviously requires sss/translucency and such.
The aberration - take it off, it’s too distracting, and for the DOF, reduce it a bit since it’s so shallow and bringing out a lot of imperfections in your render. Basically, I’m seconding everything @Photox said.
The fish shader looking much, much better. The hue/saturation is still a ways off. Here’s a google images for ‘salmon sushi’ and color swatches, next to your color.
Rice material is still off, look at refs, more glossy/wet.
Beyonf that, I’d spice it up some with washabi, ginger, chopsticks, napkins, glasses… A small scene around it. The table woo dis coming off a bit cg/plasticy. Try a tablecloth, or at least a place mat.
