Mathematics teachers can use a broad range of technologies--calculators, computers, display systems, and others--as teaching and learning tools. Simply using technology is not enough; well-intentioned activities can fall flat or pose roadblocks to student understanding, and practical issues can interfere with student success and lasting concept retention. This article describes classroom-tested strategies that allow technology not just to be used but to be used "well," enabling mathematics teachers to make the best use of the technological tools available. The author recommends keeping two goals in mind: (1) The technology must support the mathematics concepts, and (2) The technology must enhance students' learning of those concepts. Technology, when used effectively, can strengthen conceptual understanding and aid long-term retention. Students learn to formulate conjectures, make connections, and substantiate conclusions for themselves, so that they take ownership of the knowledge and spend less time as passive listeners. (Contains 5 figures.)