I'd personally pick something that you will definitely use, and is easy to grow. A few such would be beans, tomatoes, zuchinni, squash, cucumbers, onions, etc. Make a list of what you will use or regularly purchase, then see what will grow in your climate considering sunshine, temperatures and water. Pick something that should grow easily and well, then over time expand to items that will take a little more work and care. Back when I started, I went with lots of tomatoes, onions, jalapenos and bell peppers. Made a bunch of salsa and spaghetti sauce with those. You might also consider some areas where you could plant berries or fruit trees in place of some of the other plants you have.