Treat your portfolio like a new UX project. Basically, follow the UX process from start to finish with the ultimate goal of creating a kick-ass portfolio.
Conduct research with the target audience of hiring managers and recruiters. More specifically, hiring managers and recruiters for companies you want to work for.
Move onto the IA & wireframing stage. Quickly ideate on the many different ways you could structure your portfolio. Look and see how others are doing it. Explore!
After deciding on a direction, create a prototype and test it with friends and family (or people in the industry) to see if they understand your process for each case study.
Once you've gotten enough feedback and you feel confident in what you have, choose a website/portfolio builder and start creating your portfolio.
Plan on getting feedback throughout this process and continually iterating. If you truly follow this process and continue to iterate, you'll end up designing one hell of a portfolio.
