Lectures constitute a double-edged sword as teachig method--1) they allow you to convey as much information as possible in a relatively short time, but 2) lectures lead to passive rather than active learning. In many cases, depending on the time and nature of the class, lectures alone induce drowsiness in the students and boredom for the teacher. As soon as you begin to see a student's eyes roll back in his or her head, you realize the limitations of the lecture format. Lectures are often more appropriate to upper-level courses in which the students are there because the subject is inherently interesting to them, but in most cases, lectures should be a relatively small part of lower-level courses in subjects like English or history. Of course, some lectures are unavoidable, especially in large survey courses in which you strap on a mike and speak to ninety students, but I am assuming that most classes comprise no more than thirty students, which is the norm for my school.
When I am teaching writing and literature courses, I usually use short lectures in order to provide the barest common ground for understanding, and then I begin what I hope is a series of effective questions--in the form of a Socratic dialogue--to get the students actively thinking and speaking about the subject under discussion. This dialoque begins with questions of fact--what happened here?: what makes this different from what we discussed last time?--and then I move to questions of interpretation (is this work successful? how do its parts work together to create a whole? does the work speak to your experience--why or why not").
My experience with lectures--both as a student and as a teacher--tells me that lectures are efficient for the instlructor but not particularly effective for the student. Any teaching method that disengages the average student is not optimal for learning, and I would argue that the intructor's goal is to engage students quickly and continuously in as many classes possible, which requires almost constant discussion among teacher and students and among students themselves.