I picked up a D5100 a couple years ago and am still learning about photography. I thought I would explore the world of microstock photography after I heard about it from a friend. The berry picture in my portfolio was the third picture I ever took but since then I've had trouble getting acceptances.
Your food pics are a good start. The best things you can do are: -Research as to what buyers want -Get more photos up -Participate in the community -Practice! And don't feel bad if sales are slow. You have 3 pics! Good luck!