I never read any other than some of the movie novelizations.

Of those, the original Star Wars is worthwhile for a fair amount of material that differs from the filmed version.

One thing that complicates this is that Lucasfilm recently hit the reset switch on Star Wars continuity which means that all of the old novels (what they used to call the Expanded Universe) are no longer canon.

Based on what I've read, this recently published novel is probably a good place to start: Aftermath: Star Wars: Journey to Star Wars: The Forc...

I've heard Aftermath isn't good, from people who have read a lot of them. I think I'd start with any audiobook read by Marc Thompson. Star Wars Audiobook Narrator, Marc Thompson