Patience and compassion. Be patient with yourself as medicine is complicated and requires years of training. Work really hard and diligently. Be patient with your patients and remember that they are often frightened and vulnerable. When you are tired and frustrated, you must rely on your compassion to continue to make the patient's needs the priority. Above all, take care of yourself so that you can take care of others.
Each specialty is different. In my field of radiology, anatomy and pathology were the two most important medical school classes. The majority of what I use on a day-to-day basis was learned during residency.
Do not believe in cult of big names.. Treat your colleagues as fallible human biengs.. Never get carried away by those proclaiming that you are an avatar of God..Remain answerable to yourself.. Do not sell yourself to the false promise of the corporate pharma..practice evidence based medicine. Cross check every prescription and be vigilant about each and every word spoken in front of the patient.