As JoshRagem said in the comments of the question, don't lecture. Bloom published it scientifically as "The 2 Sigma problem".
Some ways I found to make a class less of a lecture (items marked with a * are covered in Lecture 6 of Teaching College-Level Science and Engineering):
- wait 5 seconds after a question (this is an eternity in front of 30+ students)*
- use a feedback sheet every class meeting, to learn about your students*
- use conceptual multiple-choice questions (individual or small groups)*
- use conceptual multiple-choice with lots of discussion (entire group)*
- buzz groups (although not easy to do when you're starting out)
- keep traditional "lecturing" to maximum 10-minute bursts, followed up with questions, exercises, etc.
Interactivity Engagement takes time during the course, which takes away from presenting "content." The solution is to not teach all the content during class time. You'll have to expect students to do the reading for the most material, and use lecture time to validate, reinforce, personalize, etc.
Although I'm definitely not the best instructor, I know I have improved a lot thanks to some other points:
- Get an evaluation from the "pedagogical resource" person at your institution (hopefully this person exists!). The evaluation was full of small, useful details about teaching. You might want to check your ego at the door, however, when you get the feedback.
- Tell your students that standard lecturing is not efficient, and that you want to raise the bar. But to do that you expect them to be prepared (to have done the reading) when they come to course for the interactive part. If I find they've not done the reading, I start to give small quizzes on the reading at the start of every course (I have 3-hour courses, so it's once every 3 courses if you have a 50-minute course period). These quizzes are multiple-choice and the questions can be used as the conceptual questions as above. The value of the quizzes is minimal in their final grade, but it engages the students.
- Tell your students that making mistakes is essential when learning. Encourage them to vote on multiple-choice questions. Sanjoy Mahajan states that "clickers" allow anonymous voting, which socially doesn't engage the students. It's important to get them to vote, but also to make them feel that being wrong is "more than OK" (because it's how we learn).
- Keep training yourself about pedagogy; try to stay motivated to teach well. Pedagogical patterns may be of interest. My students have often said they can see I'm motivated and find it refreshing. They are generally more forgiving when they know I'm trying.
- Relate material being taught to what students have learned before and will learn/use later. Anecdotes based on your real-world experience (if you have it) are useful. My students always ask me for more of that in my evaluations.
- Apply the "repeat without repeating" pedagogical pattern (Google fails me on finding a reference). Basically, it means that different learner styles (are more likely in large groups) respond to different examples, so it's helpful to repeat the same concept in multiple examples.
EDIT I recently bought this book and found it very useful because it covers many dimensions of teaching that might not seem obvious to first-time teachers. It's in a kind of check-list style, with references to external sources if you want gory details on certain techniques: Davis, Barbara Gross. Tools for Teaching. 2nd ed. Jossey-Bass, 2009.