Highschool RPs I feel are sort of doomed to a quick death anyways because of attention spans. So you may need to do something or develop something later that'll throw such a wrench in the work it breaks up the monotony of "Joey Castonaza exchanges awkward small talk with John Seinfield and they suddenly become best friends". And as said earlier: don't do the typical mythylogical/ghost/demon/hell/heaven/anthro/anime theme that tends to define the way of "different" RPs in this genre. It's not really different at all, since the basic theme doesn't change and it's all the same, just with different salad dressing.

I think there was one I was in that had some purpose for being different. But the purpose and reason for it was hardly thought out at all. Which may be another thing these sort of things lack: proper world building. A basic setting is plopped down with no standardization of the world at large. Not even basic shit like city, state/province, and country it's in. And when quirks are added that isn't supernatural: they're not given a strong meaning. So I'd strongly suggest that if you seek to break the image of the genre to consider why you're doing what you're doing, how, who thought it up/is doing, and ramble through all the questions for that to build up a proper engaging lore.

Now of course, success is also random-ass luck. So who knows.