I have downloaded 131 images, primarily soups and during my searches for specific soups I have noticed a couple of things that stop me from purchasing certain images.
1. Think before you take the picture as many of the images are not realistic, even if they are very pleasing to the eye. As an example, don't put beef stock in a fine china soup bowl - stock is used as a base to prepare soups, gravies, and stews. Put it in a measuring cup, pot or glass jar.
2. Before you garnish the heck out of a food dish, take a picture before you apply any garnish. That provides me with a base picture to add my own garnishes if I want - it's a pain to remove a couple of dozen small bits of chives to get to the base picture. It costs you nothing to shoot the picture without the garnish. Soups that appear in glasses or cups should be drinkable, if you load it with globs of sour cream or other items that don't flow when you raise it to your mouth you will have soup running down the sides of your mouth.
3. You have spent a great deal of time setting up the plate to be photographed. Take photos from numerous angles and distances.
4. Keywords - I found a picture, by accident, of cattle soup.
I can't believe that anyone would actually search for "cattle soup". The dish contains herbs - tell me what they are, not just the keyword "herbs". Tell me the kind of beans, the kind of meat and by the way the photographers that believe that you can place a whole hot dog, or full lengths of chives on top of a bowl of soup, obviously have never eaten soup! The keywords must match what I can see in the picture - if I can't see the potatoes (unless it's a cream of potato soup) don't tell me there are potatoes in it.
5. If you want to sell food pictures, I would suggest that in most cases, simple is better than complex.
I need thousands of soup pictures - keep on shooting!!