Professionalism is a must. Never, ever be unprofessional. That does not mean you should allow yourself to be taken advantage of or disrespected, which happens many times in corporate culture. But hold yourself at a standard where you are never unnerved by anything at work. Speak firmly about situations. Do not yell. Express your viewpoint but do not be abrasive. Remember to always put your best foot forward, especially when it involves your co-workers and supervisors. Remember professional growth has a lot to do with professionalism. No one will feel comfortable putting you in a meeting or seminar or in sticky job positions if you can't be the consummate professional.