The author defines 'prevention' as promoting the well-being of people through positive action that changes the conditions under which negative behaviors are most likely to occur. A prevention program must have a purpose and a focus along with four arenas of activity the author delineates as community development, personal growth and development, community problemsolving, and personal problemsolving. The author emphasizes that program planners must have an understanding of what prevention strategies are workable, what values they want to express, how to plan change, what skills are needed for prevention, and who the program's key allies will be. The three stages of a successful plan begin with orientation, training, and planning; continue with implementation and system impact; and follow up with proof and expansion. Planners should be aware of the community's and key players' attitudes towards a prevention program before implementation; the author provides a list of possible group perceptions as a way to prepare for stage 1 of the plan. He explains how to use his Youth Opportunity Planning Process to gauge community input when shaping the prevention strategy and in analyzing the results to identify youth problems and determine resource use. The author describes how worksheets and other action tools can be used to identify youth problems and possible solutions and to gauge program success, while at the same time maintaining community support. He also shows how advocacy and technical assistance can attract people to the prevention program, reinforce the prevention goal, and contribute to a successful effort. Developing local and statewide prevention networks is recommended. Worksheets and other diagrams, footnotes, and an annotated bibliography of 18 references are provided.