What ifs tend to be my biggest obstacle in professional and personal settings. I have to just remain prepared and this helps reduce any anxiety I may have been feeling about my teaching/lecture. I also set an expectation of respect for myself and other students on the first day. 

Always listen then react. Allow students who are angry to explain why and take part of the solution, if a solution is even possible. Give time for the situation to diffuse but acknowledge their concern

Informative at teaching techniques for inattentive students or center stage. Make your presense known, inspire or motivate your students with guest speakers. Creating question cards, or meeting minute notes for students to review at the end of class. 

Setting multiple reminders for due dates. Set the missed assignment standards. There will always be a 10% variable of missed assignments and not always from the same students. 

Try to touch each varying teaching style. Be prepared and take time to talk to students prior to start of class to get a feel of what the days feelings are. Demonstrations should be practiced before student arrival but always have a back up plan. Lecture for 10-15 min with mini breaks. Being a great teacher is part expertise, part story telling, part acting. 

Introduction of the students and yourself including nicknames and pronunciation. Students feel better about themselves and their education when an authority figure remembers their name. Create notecards if needed to help remember that information. 

Setting the tone in classroom settings. Allowing students to understand who you are as a person. Always keeping a notepad handy. 

You can be a friend to your students, but not a pal. Be supportive and motivative. But dont fall into the baby sitter trap. Remember that you are a professional, but that you may not always be the smartest or know best. Seek advice from your peers.