We astronomy outreachers are passionate about sharing astronomy widely—but many astronomy outreach activities are designed more by how we hope things will work than in a careful intentional way. We also rarely evaluate how well our activities are achieving our goals. As a result, many educational activities must be significantly less effective than they could be. Fortunately, there is a large body of education research on how people learn. If we are serious about sharing astronomy widely and effectively, we must treat our teaching like research: (1) Have clear goals for our outreach, evaluate how well we are achieving our goals, and revise our strategies in light of what we learn; and (2) Use appropriate teaching techniques supported by education research wherever possible.