This booklet is designed to help users understand the skills and concepts needed to develop effective computer assisted instruction (CAI) programs in any computer language and to polish and extend BASIC language programming skills. It assumes some idea of CAI and some BASIC programming (but not fluency), and can be used for self-study, in a workshop, or as a text in a computer education course. Examples are written in Applesoft BASIC programming language, with footnotes assisting for other BASIC dialects. An introductory chapter establishes the context for the rest of the booklet, and the second chapter gives an overview of the ways in which traditional learning theory interrelates with the writing of CAI. Each of the remaining chapters deals with a factor that should be considered when writing CAI, including controlling the screen, checking answers, user control, providing appropriate tasks--controlling randomization, rewards, and response verification. Appendices include a computer literacy review program, "case" structure for multiple tries, multiple re-asking in response to wrong answers, a music routine, and an approximately timed input interrupt routine. (LMM)