A common desire among music educators is to help students develop the ability to reflect on and evaluate their own music making. To achieve this goal, music educators often provide their students with a variety of instructional activities, such as watching their ensemble's latest concert performance and writing a critical review of it, allowing students to independently prepare to perform alone and in small groups, and asking students to identify and reflect upon both individual and ensemble musical goals. Such activities can lead to increased self-awareness and reflective thinking, opening the doors to meaningful musical growth. One teaching tool that may be useful is the portfolio. Because portfolio contents are usually selected by the students, portfolios require students to reflect on their work, assessing the work's quality and documenting their progress. In certain kinds of portfolios, students then formalize this knowledge through written reflections that become a guideline for reviewing the portfolio's contents. The process of creating a portfolio also provides opportunities for reflection as teachers and students engage in contextually rich dialogue. There are five "key steps" for creating and using portfolios: (1) specify purpose; (2) provide guidelines for selecting portfolio entries; (3) define student role in selection and self-evaluation; (4) specify evaluation criteria; and (5) use portfolios in instruction and communication. In this article, the author discusses each of these steps in detail, sharing essential principles and suggestions for implementation. As each key step is described, she relates it to a sample portfolio intended for a small-group or individual performance project. Although the sample portfolio is designed for use with choir students, it can easily be altered for use with other types of ensembles or classes (e.g., band, orchestra, group keyboard, songwriting classes, guitar classes). This sample portfolio is designed to be used with high school students. For use with younger students, a teacher would need to simplify the language of the guidelines and consider requiring fewer artifacts. A teacher would also need to carefully and thoroughly explain each element of the portfolio in depth, should provide examples of excellent and poor work, and should provide a more detailed description of the work. Also included in the sample portfolio is a suggested timetable for completion of each required element. (Contains 2 figures and 18 notes.)