Study your audience and learn their biases and preferences. In a classroom or work setting, this requires interacting with your students/colleagues on a group and individual basis. In a presentation setting, this requires learning about the audience ahead of time, which can be done either by reading information about the audience, for example profiles for a conference, or asking the manager of the event what type of people will be present.
Research the topic at hand thoroughly before provoking the audience. If you know the topic inside and out, you will be more capable of presenting valid objections to the ideas held by the audience, thereby instigating alternative thinking.
Ask questions that provoke the audience into questioning their assumptions. The Socratic Method posits that you ask "Why" and "How" to all questions, forcing an audience to question their assumptions critically. The other "W" questions--Where, When, and Who--can also promote alternative thinking by forcing your audience to consider all sides of a concept or situation.
Present information that is contrary to the assumptions of your audience. For example, if the standard assumption at a business meeting is that only students with an elite business education ought to be hired in the next term, then present information that explores the business potential of people that come from more varied backgrounds, for example a science, politics, artistic, or non-academic background. The phrase "there are at least two sides to every story" is apt here. Whatever the assumption of the audience, research its opposite and present that information to provoke alternative thinking.
Compel the audience to debate their ideas. For example, you could pose a question for the audience, and then request another person to disagree with the initial statement. If no one disagrees initially, then become the focal point for disagreement yourself, constantly arguing against what anyone else says.