I’d say the best way to present your portfolio would be to give potential clients a presentation (as opposed to just sending them a digital file through email and saying “this is what we’ve done”).
Bigger is better so a projector helps (especially if you’re presenting to more than one). You can then methodically take them on a “journey” through each of the Social Media campaigns you want to present & describe why you did what you did (without giving confidential info away) and follow up with what success you got from each campaign and how your analysis has helped plan the ongoing success of these and future campaigns.
They’ll really want to know that you know what you are doing and that you deliver results – don’t get too technical with online or Facebook jargon with them, they probably won’t care much for that.
I wish you all the best acquiring many more clients