Make a personal fireworks show.

Fireworks themselves are romantic but you can make them a little more romantic if you put a little effort into it. Find a secluded spot that now one else is at and park the car there. Either spread out a blanket in the grass or get a little padding a spread it out on the hood of the car. Make sure you can lay down and watch the sky show. Don't put extra strain on your neck looking up into the sky. Hold hands and watch as the sky comes alive. It will seem like you are the only two people in the world watching this display. Now if that isn't romantic I don't know what is.