Engage
As a leader and Instructor of your class the most important factor is that you must keep adult learners engaged, they will most likely drop from school if they do not feel it's worth their time.
I agree wholeheartedly. There are so many other life factors that contribute to poor attendance: From family issues to illnesses to flat tires, the litany of personal problems seems endless. For that reason I know I have to make it interesting, motivating and, yes, fun.