1. Don't tell. Anyone can stand in front of a class and tell students stuff they don't know. A good teacher will always start with a problem, encourage students to suggest their own solutions and then proceed to tell the class the actual solution. Most good teachers I have encountered use a variation of this method to teach. It not only works well, it gives students a sense of accomplishment.
2. Let students come to their own conclusions about the subject material before you correct them. College students are not stupid. I've seen that the worst teacher will always tell students to "slow down for a moment" just so he can meticulously read through his shrink-wrapped bullet points. Boredom ensues.
3. Ask. Ask many questions. Heck, teach entire chapters as a series of questions.
EDIT: spelling, grammar, lameness.