Cross-age teaching occurs when someone shares skills and knowledge with another person who is older or younger. Cross-age teaching of crime or substance abuse prevention skills by students can prevent or reduce crime. This bulletin contains suggestions for starting a cross-age teaching program through the following steps: (1) determine the focus; (2) find students; (3) research the subject; (4) develop lesson plans; (5) seek advice; and (6) practice. Tips to keep the program going, what to expect from program operation, and how to evaluate the program are discussed. (SLD)