Hey there, I did my English oral a few weeks ago.

As I see it, the persuasive oral is kind of like an inverse language analysis. It's supposed to show how well you understand persuasive devices and the extent to which you are able to effectively utilise them. As such you should try to put all of that metalanguage to practice. Adopt a tone, employ rhetorical questions and use repetition to reinforce your point. Connect with the audience with inclusive language; invoke concern over their financial status; cite statistic or evidence; appeal to the greater good. That's what a persuasive piece is all about.
Since it is an oral, 50% of your grade really comes down to the delivery, so practice thoroughly. Know your speech well enough so that you only need to glance occasionally down at your cue cards. You're not reading out chapters from your textbook, you're giving a speech.
In terms of beginning the oral, my topic was asylum seekers, so to establish empathy I gave a little spiel placing the audience in their shoes. Also, do know that there's a lot that can be done with pacing and varied sentence length to capture the audience's attention. In my conclusion I really emphasised repetition with phrases like " I challenge you. I challenge you to....etc" while maintaining eye contact (... staring into Mrs S's soul....)
All the best for your oral!