I have learned how to better help with rowdy students and to get the class back on track, How to deal with students who play the "blame game" and to quiz the students on the class rules and regulations in the begining of the session to make sure they herd and understood.  

I learned different tips for motivating the students for a new course.  As well as the "what I thought was going to happen" vs what actually happens approach, and expectations vs requirements.  

I've learned to look at pros and cons of previous instructors of mine to see what worked and did not work in different situations throughout the field.  Also to make sure the intended mission and philosophy of the school aligns with how I do the position I am in.