The galaxy far, far away may not have too many heroines, but thankfully it does have Princess Leia Organa. She might not seem the most likely candidate for being a powerful character, but just try and imagine the Rebellion succeeding without her. As the daughter of Bail Organa, and a member of the Alderaan Royal Family, she's an incredibly important figure in the galaxy, but unlike so many real-life Royals she actually serves a purpose, and uses that political power for good, having huge influence in the Imperial Senate and later in the Empire-toppling Rebellion. She risked her own life by being entrusted with the plans to the Death Star, and was the one who thought of enlisting the help of Obi-Wan, which brought him and Luke together and kick-started their entire quest. Even after witnessing her planet be destroyed she remained strong, and kept fighting the Empire all the way, playing key roles either in a more strategic and leadership capacity, such as on Hoth, or in the heat of the battle itself, like on Endor. Of course, she's more than handy with a blaster, and is also Force sensitive, which just about tops it off.