ScienceWoman, then Neurotopia, have posts on lecturing that generated a lot of comments. Useful stuff for anyone starting out to teach. I think everyone develops their own answers to lecturing, but I want to point out a couple of broad patterns of thought, using swimming as an example.
You can teach people to swim by throwing them into the deep end of the pool where the diving boards are. Some will learn by this method, but many will drown.
You can also teach people to swim by starting them in the shallow end of the pool and actually instructing them. It’s slower, but you'll probably end up with more people actually swimming by the end of it.
Many university instructors teach using option one. This is frequently supported by statements like they want to challenge the best and brightest students in the class; that they are maintaining the quality of education and refusing to dumb down their instruction; students have to be responsible adults who learn on their own; and so on.
I personally find this a terrible wasteful of human potential.