The effective evaluation of educational projects is becoming increasingly important to funding agencies and to the individuals and organizations involved in the projects. This brief "how-to" guide provides an introductory description of the purpose and basic ideas of project evaluation, and uses authentic examples from four different astronomy and earth/space science projects to illustrate important ideas. Topics depicted include types of evaluation, selection of an evaluator, alignment of evaluation activities with project goals, and different methods of data collection in evaluation. A list of additional resources, including professional organizations and selected journals, is provided. (Contains 5 notes and 2 tables.)