Put on an Electric Touch and shake everybody's hands. Kidding, but that was actually half meant. Put in some patter with that. Do it to insinuate your magical and literally shocking presence.
-Produce campaign materials out of thin air and out of your mouth.
-Do Popfist during your grand entrance.
-Take out your written speech (on flash paper) and burn it, then produce a picture of yourself, smiling. You then proceed to sign it and toss the picture to the crowd.
-Do an ACR. Present yourself as the ambitious card, and rise to the top.
I got that "rise to the top part "from a T11 forum member's signature, sorry but I forgot who.
-Do a torn and restored card effect with a rectangular picture of your school logo or whatever it is you want to represent. There's symbolism here. Restoring the school to its former glory, giving it what it really needs and what it's missing, making it complete once more, visualizing how you will make the school better, repairing the damages from past mistakes, etc.
These are just some of my ideas. Really, times like these get your creative juices flowing as to what other uses magic has.
And by the way if you plan to do close-up effects on a huge venue, have a camera, projector, and a screen ready, so everyone can see what you're doing.