Active learning refers to techniques where students do more than simply listen to a lecture.
Research shows greater learning when students engage in active learning.
It is important to remember, however, that lecture does have its place and that you should not do active learning without content or objectives. Thus, you need to prepare students. Explain your objectives and the benefits of the active learning techniques explicitly to students. Expect both successes and failures as you try active learning techniques. Solicit feedback on the activity afterwards from the students to improve it in the future.