Need to stabilize Digital SAT R&W score in 1 week (Fluctuating 710-800). Non-native speake

I am taking the Digital SAT in a week and need advice on how to improve the consistency of my Reading & Writing scores.

• Background: I am a non-native English speaker, but my reading comprehension is solid.
• Current Situation:
  • I scored 780+ on all Bluebook tests.
  • I am taking full-length practice tests provided by a tutor friend. My R&W score is highly inconsistent, swinging anywhere from 710 to 800 depending on the test.
• Goal: I want to stabilize my score at the higher end of that range before test day.

Since I only have one week left, what is the most efficient way to study and reduce this variance? Are there specific strategies for reading questions that help eliminate silly mistakes? Any advice for a non-native speaker looking to lock in a consistent score would be appreciated.