George Lucas planned to score the film with existing classical music like Stanley Kubrick had done on 2001: A Space Odyssey before Steven Spielberg introduced him to composer John Williams. Lucas and Williams agreed on a classical 19th-century Romantic music style with liberal use of leitmotif for the score. Since the movie would show worlds never seen before, the music had to serve as an "emotional anchor" for the audience to relate.
In earlier drafts, including the ones that were used for audition readings, the planet Alderaan was known as Organa Major. Although the name was changed, the "Organa" was retained and became Leia's adoptive family name.
At one point, George Lucas had planned the character of Han Solo to be a huge green-skinned monster with no nose and gills. Then Lucas changed the idea of Han Solo to a black human. He auditioned several black actors and even musicians (including Billy Dee Williams) until finally settling on Glynn Turman. But after this he decided to make the role white. Kurt Russell, Nick Nolte, Christopher Walken, Jack Nicholson, Al Pacino, Chevy Chase, Steve Martin, Bill Murray, Robert Englund, Sylvester Stallone, John Travolta and Perry King were all candidates for the role of Han Solo. George Lucas also wanted to stay away from any actors he had previously used in his films. James Caan, Jack Nicholson, Robert De Niro and Burt Reynolds turned down the role. Harrison Ford (who had played Bob Falfa in Lucas's American Graffiti) read the part of Han Solo for screen tests of other characters but wasn't originally considered for the part. During these tests Lucas realized Ford was perfect for the role.
Most of the Stormtroopers are left-handed. That is because of how the weapons are constructed. Their weapons are based on a real weapon, where the magazine is on left side of the weapons. This construction caused it to hit the troopers in the chest. Therefore they have to switch grip of the weapon, which made them look left-handed.