I make my student portfolios with binders, so that work can be added or taken out throughout the school year. We use tabs to separate each of the Common Core strands, but they could also be done by subject or IEP goal. I like the binders that have the plastic covered opening on the front, so students can slide their portfolio cover page in and make it look very official.
We decorate our student portfolio covers on the very first day of school.
PRO TIP: Student portfolios are perfect for documenting RTI!!
Happy Teaching (with Student Portfolios)!!