If an important goal is for our students to treat each other with respect, then the responsibility for model ing respectful communication is on you.
Words can be very powerful. Be careful how you use them.
Be sure that your words focus on the behaviour not on the student. There is a very big difference between saying, "You are so lazy!" and, "You haven't done your homework."
Teacher remarks should be about behaviours. Students should know you value them even when you have to address areas that need improvement.
It is important to remember that some of our students wil test us to see if we can maintain our respectful attitude even after they push our buttons. Never personalize students' remarks or behaviour.
Always remember that often the child who acts like they need approval the least is the one who needs it the most.