This video demonstrates how to teach students the proper playing position. To achieve this effectively, the teacher verbally instructs students through each step while students observe the teacher model the correct behavior. After the sequence is complete, the teacher should ask the students to stand and then return to the proper playing position.
It is likely that you will have to correct students and make minor adjustments to their sitting position throughout the early months of study. The key is consistency. Make it known to students that sitting with the instrument this way makes it easier to achieve fantastic tone on the guitar and to play beautifully. It is also a good idea to provide the performance checklist (found in the Beginning Course Packets) for each student to reference while establishing position.
Demonstration of teaching proper playing position.