Set up a one-on-one meeting with the teacher. Embarrassing the teacher in front of his peers won't accomplish anything. A one-on-one meeting allows for a free exchange of ideas and thoughts.
Avoid being confrontational with the teacher. Explain that you simply want to help him improve as a teacher. If you are confrontational, you are putting the teacher on the defensive, which makes it harder to work together.
Create a plan of action for the teacher to implement in his classroom. Adjust this plan of action during your meeting based on ideas presented by the teacher.
List the goals you would like to see the class achieve through the implementation of the plan of action. For instance, set a realistic goal for increasing the average scores of the class. If the class is scoring below average on state tests near the beginning of the year, aim to bring that score up to average by the end of the year.
Present statistics to the teacher to show how important it is that he help the students strive to do better. For instance, AchievementFirst.org reports that fourth graders in low-income communities are already three years behind in school, and half of them will not graduate high school. Showing the teacher that he can make a difference in the students' lives can help motivate him to improve his teaching techniques.
Offer your help in any way needed. Let the teacher know that he can come to you for advice and ideas to help improve his students' performance. Help the teacher locate resources to use in the classroom to help students who have special needs, such as attention deficit disorder or dyslexia.