Your portfolio has one job — show clients that you can deliver results for someone like them.
The good news: you do not need prior freelance clients to build a strong portfolio.
You need to show that you understand the work and know how to execute it.
Every portfolio item should answer one question in the client's mind:
"Can this person actually do what I need?"
That means showing outcomes, not just tasks. Not "I managed a project" — but "I coordinated a 6-person team and delivered a product launch two weeks ahead of schedule."