Professor Tyler Cowen of Marginalrevolution blog, lists these qualities of a good, no great teacher:   The most important lesson is to use the right textbook. Other than that, he lists:

• 1. Give a damn.
• 2. Get to the point when you speak.
• 3. Expect something from them.
• 4. Teach to the students who are interested in learning.
• 5. At all levels, do not overestimate the attention span of your audience.
• 6. Do not be afraid to be idiosyncratic, provided you adhere strictly to #2.

From the comments:

• 1. lecture preparation: Have a plan, have talking points. Have good short precise prepared sentences for major concepts and don’t wing it and ramble on the spot. Like a seminar.
• 2. examples/stories. Good examples bring life to concepts and theories and make it a lot easier to remember the generalities.
• 3. ask them questions, let them guide some of the discussion. Ask them what they would do, keep them engaged and awake. Group work also helps because some of them will ask each other stuff they won’t ask you.
• 4. Repeat, repeat and repeat. people’s attention will drift in a 75 minute lecture.
• 5. Have fun. If you’re in love with the subject and excited about it then you will be a lot more bearable and will make the class fun even if the subject itself doesn’t hold much appeal to your students. 6. Be firm with your policies. Students respect harsh, demanding but fair policies but if they see that you wanna please them then they will exploit that. Nobody likes a pushover.

Read the whole post for more great teaching insights from commenters.

From another list of great tips for teachers:

• Illustrate the Movement of Thought - people learn by example. Don't just provide an algorithm for solving a problem: act out how your students could discover how to solve it! Illustrating mistakes is just as important as showing how to do things right.