Maintain a positive attitude. It is important that your child perceives the teacher as a smart and competent person of authority. Watch and listen. Assess the situation before you take action. If you've heard negative things about the teacher, but haven't experienced any problems, don't jump to conclusions.
Every situation is unique.
If your child has complaints against the teacher, be sure they're legitimate. Sometimes children want to be moved to a class with friends. Finally, the start of the school year can be difficult for younger children. If you immediately make a big deal, it sends the wrong message to your child. Meet with the teacher.