Being early, prepared and ready to greet your class with enthusiasm on Day One really sets the tone and establishes professionalism. Knowing their names, being approachable and enthusiastic about the subject matter helps keep that momentum throughout the class. 

Always be the first one to class, it will give you more time to set up, help maintain a professional appearance and interact with your students. Taking the time to review the lesson plans and create detailed check lists helps keep the flow of information in class, while allowing for more student interaction. 

Being in class early to greet my students them as they arrive, as well as, having my lesson plan and presentation ready to go before I arrive to class is a great way to demonstrate professionalism to my class.