See Bryan Garner's How to Write Powerful Closers. Avoid the rote and perfunctory. Instead, try "a pithy summary that contains at least two catchy (but not catchpenny) words that you haven't used anywhere else in your brief or motion. Keep it understated. But know that this is the place, if there is one, to begin injecting a little emotion." Or "make a policy argument that might not have fit well in the body of the brief."
The point is to find some way of making your points a little differently at the end. Rack your brain to think of the approach. I like to write the conclusion in a separate sitting, without looking at the introduction or the body of what I’ve already written, but trying to find a slightly different angle. Just as a photographer finds that moving a step or two one way or the other changes the view significantly, you can try doing that with some original thinking.