Wheat is your most important starting crop. It is required for all the beginning basic ingredients. The next most important crop is corn. With both those crops, you can sell them as is for quick money and experience, but they can also be used to feed your livestock for milk and egg production. Corn and wheat are also required to make biscuits and cornbread. Get a good supply of wheat, corn, milk, and eggs to get enough income to expand your farm to get more crops and animals.