I'd say that a good cook should have the proper training--in theory which is gained at school and actual practice. However, he will be the best cook if, in addition to his acquired skills in school and in practice, he puts his heart into his cooking all the time! Thank you.
I think anyone can follow a recipe but what it takes to be a good cook is the desire to be good, an overall desire to make good food. My daughter and I can both follow a recipe and mine will be okay. Her version will be awesome because she loves doing it and may add little of this or that and it becomes awesome.