your work is very good. your materials look correct and the lighting and composition are also very good.
but, your images look flat with no contrast. are you using something like between 2 and 5 highlight compression and 2 to 5 contrast or something like that? you are missing some photoshop editing. mess with the curves in photoshop contrast cameraraw and saturation, push your images. you'll be amazed by how different and punchy the images will look. I took the liberty to edit two random images of yours. very quick edits two minutes for each image and they look much more interesting. no magic, it's contrast HC shadow lift blacks whites saturation etc.