If everyone else is thinking outside the box, you can do something very traditional and straightforward. Classic and traditional usually works well. It's easier to plan. It's had all the people go before you hammer out the path. If everyone else is flailing around trying to do something new and failing, traditional looks very nice.
Or you could do something from another perspective -- possibility still being traditional when doing that, but doing something tradition from a different philosophy. Take a different philosophy or do things the way a different culture does it. That might not necessarily take a lot of extra work but could look revolutionary if no one around you is familiar with it. Or I suppose it could look pretty stupid, but definitely outside the box.

"Do not try to think outside of the box — that's impossible. Instead, only try to realize the truth: there is no box."

"Dude. Check it out... This kid just like totally mangled this non-existent spoon. Narly.... I wish I had some non-existent soup for my spoon that's not here. Or I could kill a man with a spoon, a spoon that's not there! Muah! Oh and that kid really needs a haircut."
The next time your teacher tells you to think out of the box, give him the mystic "There is no box" line.