Teachers give a lot of feedback, and not all of it is good. This article discusses how to ensure teachers are giving students powerful feedback they can use. For feedback to be effective, teachers need to clarify the goal of the lesson or activity, ensure that students understand the feedback, and seek feedback from students about the effectiveness of their instruction. The three levels of feedback--task feedback, process feedback and self-regulation feedback--are discussed. Tips about what types of feedback work, and what types do not, are also provided.