The first thing you need to do is figure out why you are against sameness. Is it the loss of individuality? The lack of personal expression? One of the reasons why I would not want everyone to be the same is because it implies that someone else is in control and making choices about what is ok for you and what is not. Think of all we would lose if we could not express individuality. Would there be music? Would poetry not be written anymore? Could we root for our favorite team or wear our team's colors? Do some more thinking on the subject, and I'm sure you'll do fine.
Another thing, I know teachers say that you need to have some kind of "hook" to draw readers into your essay. My feeling is that if you express your beliefs in a clear and convincing way, you won't need to resort to using tricks; besides most of those "hooks" end up sounding a little corny!