Luffy's dream is to be the Pirate King, Zoro to be the best swordsman in the world, Sanji to find All Blue etc etc.
If you were a pirate, what would your dream be ?
Just think for a moment. Look at your personality and how you would be as a pirate. It could be the same dream as Robin, to find the true history, or maybe like Nami, to draw a map of the world, or maybe a dream that only you have.