Look for the codes of ethics in your own discipline and begin to read and understand what will be expected of you as a professional in your field.
This one is very interesting to me because reading the code of ethics is easy. understanding and following them is different and not everyone honors or understand it. What is expected of you in your field should be small part of professional field. what makes you professional is understanding youre job is the education and learning time that goes into it before getting hired.