Statistics can help. Combing them with examples can be powerful. Using too many statistics can be deadly. You should qualify the sample, translate the statistics that you use so the audience can understand fairly. Relevant visual display of statistics can be a powerful aid in making an argument.
Personal testimony can also provide dramatic support material.
Testimony can give emotional life to the issues you're focusing on. You should of course quote or paraphrase accurately and fairly, identify and qualify the source's credentials. Though particularly appropriate when you're seeking a commitment to personal action, the suggested sequence can provide good structural ideas for any sort of persuasive presentation. I. Students seeking careers in HR often have a problem. Every year many jobs are available, but require appropriate internship experiences as a bare minimum.