ah, the conclusion is always a stickler. but here are my suggestions
restate your thesis in a slightly different way and back it up with your other main points. present the other side of the arguement, but show how your opinion is better using examples.
present some insight on your ideas, take it to a higher level of thinking.
present something to keep the reader thinking, like a rhetorical question.
make yourself seem smart by explaining something about your subject like irony, paradox, whatever sounds intelligent and philisophical. just make sure it makes enough sense to be acceptable.