The problem with all competitions is you have to rely on the vagaries of the judges. Without knowing their personal preferences it is impossible to know. Their preferences might be photographic, in which case lighting and framing would be paramount, or if they are foodies best examples of subjects might win, or anything in between!
Best advice, shoot for yourself, to your style. From a photographic point number three is the best technical example, but it is also the most boring. You really need to control your specular highlights on the other two. Number one is the most emotional, but the background is distracting and too bright. Olives and cheese make me think warm, summer, comfortable, your scene is cold and hard. I'd get some cloth in there; glass steel and blue are as far from warm, summer, comfortable, as you can get. Also they are not complimentary to a brown with oil, I'd be thinking wood, sack cloth, candle etc. But that is just me and my thought process, I am not important for your competition
Hope this helps.