Research for story ideas for my story bible.
Have you considered non-SF series? "The Hidden Fortress" by Akiro Kurosawa was the inspiration for Star Wars, and "Forbidden Planet" was an adaptation of Shaekespeare's "The Tempest". Don't forget also that Joe Campbell, the mythologist, has said that there are no new stories, just retelling of older ones.
I'd consider reading many good SF books as well.