Indexes are used to improve query performance. As a result, good indexes are designed around queries that users find important in their application. This talk presents three simple and effective rules on how to construct indexes around queries that result in good performance. The rules are explained using a simple model that does NOT rely on understanding B-Trees, Fractal trees, or any other data structure used to store the data on disk. They are derived from these simple properties: point queries are slow and range queries are fast.