Decide of the subject of the portfolio. If there are to be multiple subjects that focus on specific topics in a curriculum such as art or writing, it is best to have separate portfolios for each subject area.
Determine the size of the portfolio needed based on the amount of or size of the work being placed in it. For example, if a portfolio will house medium to large sketches, then you will need to make or purchase an art folder. On the other hand, if the portfolio is for a semester length writing course or for a drawing done on construction paper by a kindergartner, then a simple binder or notebook can be ideal. A clear notebook, for instance, with individual plastic covers gives children a chance to protect their work.
Go high-tech by scanning in the student's work and saving student portfolios onto an office or classroom computer, either as the portfolio itself or as a backup copy. You can password protect these files if desired.