CB’s official tests should always be your primary source of study material. Save test 6 for last, as it is the hardest. There are currently 7 tests available, #4-#10. Tests 1-3 have been shelved.
Also, use the question bank and filter for Hard questions and questions that don’t appear on current practice tests.
Edit: Start from scratch with your bluebook tests. Retake them, starting with the first one you ever took.