You must stop. Flash is killing your food photos. It’s making them flat in color, plastic-looking (by appearing reflective), and blown out, which is when the highlights are too white. Turn the flash off and familiarize yourself with the light in the area, maybe sit by a window, and learn more about your ISO function. But your on-camera flash, pointed directly at your food, is just making your photo look like a bad American Apparel ad. Soft window light will bring a whole new life to your food. Both these two images had high potential for "nasty flash" (see how reflective the egg whites are, even without a flash?) so I placed them near a window and voila — now they look super delish.
Your food is ugly.
Let’s face it, some food just isn’t pretty, but that doesn’t mean it isn’t delicious. Spend a few moments looking at the dish and really envisioning how it’s going to look before you snap that photo. If it's not the best-looking food in the world, take a moment to add a little color (something like a red pepper, sour cream, or a flower) or include objects to spruce the image up (cutlery, chopsticks, maybe a colorful napkin). This bowl of soup could have easily looked boring, drab, and maybe a bit like a bowl of dog food if done wrong. But adding in some cutlery and background, getting lower — so that it's more of a scene and not 100% about the soup alone — brought it to life.
Your image is awkwardly busy.
A bakery case full of fresh, steaming cinnamon buns makes everyone happy. But a photo that has too much going on — crowds, reflections, the food, staff, signs, menus, and more — becomes too much. You are there and experiencing the moment, the smells, and are probably salivating over your next bite — how can you make your viewers experience that without overloading the picture? Step back and focus on one of the details. Highlight it and make it the hero of the photo. Maybe it's the steam, maybe it's the icing, maybe it's a staff member reaching to grab a bun.
Bring the viewer in by excluding the elements in the scene that are perhaps distracting (glare, other customers, other food) and bringing attention to the delicious details. In both these shots, I excluded busy scenes to bring the viewer's eye right to the point.
You're awkwardly close.
The opposite problem of the above — you're getting so close that your cheese plate looks like the surface of the moon. Viewers need context; they need to know what they're looking at. Macro images can be great in a long photo essay, but if you're taking just a single shot, back off a bit. Remember — details are great, just be sure to give them a bit of space.
You're overthinking it.
Arranging and rearranging the plate. Adding props. Removing props. Moving the whole plate around the restaurant. Trying your flash out, switching to your macro lens...now your food is cold and some of the compelling elements of the scene are gone. If you're inspired to capture the moment, that's great! But stay in the moment. Maintain the authenticity of the location, the food, the flavors — and be inspired by them. Then, put the camera down, tuck in...and enjoy.