Carmel, CA 2013 - Food photography
Please forgive my wordiness here:
For photos 1 and 2, it's the food itself that could use some help through food styling. I'm not sure how much experience/interest you have in this field, but basically it's arranging food in the more attractive way. This might also include making sure that none of the food is stuck to the white plats/bowls, for example. While the food in these photos is relatively well-styled, it could still use just a little help to make it better.
Here is a video about how McDonald's styles their food. [link] Obviously, however, you can't do all of this in a restaurant, but I'm just trying to show you the possibilities.
Photos 3 and 4 are the nicest, mostly due to the lighting.
Photo 5, as others have mentioned, could use a less distracting background.
Other than that, some general tips are to keep the angle either on level with the plate (lower than you would normally see it) or directly above it. The last thing you want to do is take a photo of the food at eye-level - that's how people are used to seeing their food, and therefore, it's boring for the average viewer. Beautiful shots, though!