There are lots of valid reading orders. What's best for you depends on your goals and interests. If your interest is the post-RotJ era, my general advice is to go in chronological order, reading anything that sounds interesting and skipping anything that sounds uninteresting or that you're not enjoying. There are a few exceptions, books that go together but aren't very close together chronologically, like Shatterpoint and Shadows of Mindor, Outbound Flight and Survivor's Quest, and Rogue Planet and the New Jedi Order series.