Identify all your high achieving students and all your struggling students by looking at your student's past work, grade point average and assessing his or her participation in the class. You might also want to consider giving an achievement test that will identify which students are understanding the class material and which are not. With the students identified, you then create a seating chart.
Create a seating chart based on what you have learned. Label the chart with special symbols like an ampersand, bracket, comma, or question mark to identify that student's level. The markers are helpful because you can leave your seating chart out without worry about prying eyes, and you can still know what that student's level is.
Strategically sit the students in rows or groups. For every high-achieving student, sit one of two struggling students next to him or her. You are doing this so that when the students interact, he will be placed next to someone that has an easier time understanding the material. This will encourage peer interaction, and you will see that all students benefit.
Identify the students that are struggling and that shy away from participation. Place those students in the front of the class, that way you, the teacher, can interact more with them. Sit high-achieving students next to this student so she can get the most from being in the classroom.