An essential part of good teaching is getting students interested in what you have to teach them. After that, you just need to point them in the right direction, to give some encouragement, and perhaps to help them to refine the quality of their work.
It is clear that students, then, must be involved in the learning process. They will not, for the most part, become interested in something unless they have some ownership. The best way to establish that ownership is to ask your students an interesting question, one that they perceive as being authentic and that they cannot immediately answer. Such questions will vary depending on the student, but it is the job of the teacher to think up these questions and to devote considerable class time to allow students to work on them, individually at first, and then collectively.
I do not mean to imply that thinking of these questions is easy, just that it is essential. Many of us were taught by teachers who thought that their main job was to provide clear explanations of the concepts that were in the book. We must recognize that this approach is backwards. The clear explanations need to come after the students have figured out how to solve the problem, or at least after they have worked on it long enough to care about a solution and to want to know.
It is also best if the first attempt at this explanation comes from a student, so that the class is actively thinking about the validity of that explanation. When the explanation comes from the teacher, students tend to write it in their notebook without giving it much thought. When the explanation comes from a peer, students tend to be critical and open minded, trying to find a flaw in the argument. The second is a far better way to learn.
-- John Benson