I personally have developed a portfolio for a masters program. What we did was to bring to the seminar each week two items that would be presented to a small discussion group. The choice of the item was to be evaluated on how this item reflected our professional growth. We could include items that we perceived help to tell who we were as individuals. Each item was shared and were to write a short reflection on the selection and how we feel showed our professional, academic or personal growth.
Some members use it in job search and others keep it as a reminder of strengths.
We used clear plastic sheets to house each piece. It protects the items and makes it very useable. Our professor, Dr. Nancy Healy, had examples of children's portfolios and her personal portfolio as examples. In addition we did other research. What we gained from research is that there is not one way to do a portfolio.