Nothing is more important.
Watch a lot of current movies or at least track them. What actor is hot and what they are looking for, or well suited for. If the screens are crammed with a slew of sci-fi flicks, avoid them like the plague, by the time you are done, it will be a cold trail to nowhere. Look for a genre that has done well in the past and has been under-represented of late. Better still, find a staple.