The modeling and basic texturing of most of this is an excellent start.
The counter door/wood especially is very “flat” I think more bump would help, as well as some “dirt” via spec, etc. Look up some of the “making wood real” tutorials.
Definitely too much “fish-eye” - the camera focal length is so extreme the plaque looks badly warped, its not bad on the counter.
There’s no diffuse light from outside spilling in on the counter.
The wall electrical recepticle looks is too thick with that heavy shadowing, ie, out from the wall too far, but the sink looks to be floating because there isn’t any. The calking mentioned might help that. Or else a slightly-shadowed edge between the sink and countertop.
The chair and faucet black metal looks VERY flat. Needs variation and highlights.
The background picture looks fine - very realistic! Oh, you mean, matching it with your foreground?
Notice the light quality, colours and sharpness? The spill from the window into the room will be a warm, yellowy light rather than a plain diffuse blue-ish sky lighting. That will help pull the two together.