This document discusses team teaching and provides advice for effective collaboration between co-teachers. It outlines Tuckman's model of group development and advises teachers to establish clear norms and expectations up front. The document lists dos and don'ts, such as being considerate of workload, marking responsibilities, and ensuring equal value is given to both subjects. It also provides suggestions for what teachers can do when their subject is not the main focus, such as running tutorials, asking students questions, and learning about the other subject area.