The first file has a white balance issue. It is too blue. Also the motion blur of the moving water is distracting. You needed a faster shutter speed to freeze the water motion. It also has noise grains.
Most of the second file is not in sharp focus and also it's under-exposed.
The third file is noisy and lines around the edges as if excessively compressed. That file too is under-exposed and not in sharp focus. There are several IP elements in this picture. You need to remove all brand names and logos.
The file with the nails is completely out of focus. It too has IP and white balance issue. The highlights of this file is too high.
The final image is noisy, blurry, has a white-balance issue and not in sharp focus.
You need to inspect your files at between 100 and 200% magnification to fine most issues.
You need to stop taking pictures of products, though. Jewellery, chocolate, tobacco heaters, perfume - all of these belong to someone else, so you cannot claim copyright and cannot sell them as stock. (By "belong to someone else" I mean copyright. Buying a chocolate bar gives you the right to eat it, but not to sell copies of the design of the wrapper).