A long time colleague used to say, "I'm going to teach them ecology if I have to rip their little heads off and pour it in." Such practices are widely frowned upon among the more enlightened members of our profession, but short of pouring it in, you can't make students learn anything that they are not interested in. Therefore the first and most vital step in teaching, especially subjects like botany and ecology that are viewed by many students as "boring" is to generate interest. Here's a nice post about how an aquarium visit generated student interest in ecology (and a link to a freebe publication), but generalized there is a lesson for all educators. Put something interesting in their hot little hands. The most successful general biology lab for non-science students the Phactor ever constructed consisted of a series of stations each with some intriguing problem that posed questions to be answered via a simple investigation by a small group of students.