Rebecca and The Lovely Bones comparison for English Literature ?

For my AS level course I have to write and comparison essay on 2 books, both have to be post 1900 and one post 1990. I've read The Lovely Bones, by Alice Sebold, and I'm over half way in Rebecca, by Daphne du Maurier. I was wondering if you could think of any good aspects to compare and contrast in the two books for an essay. I was thinking of the themes of death, memories or even love. Do you have any ideas or tips? Thanks!