Just hang with the pack for the first 600. Anybody can run a 600. Focus on the next 400....from the 600 to the 1000....most HS runners lose focus during that part. Not you, focus on form and breathing, and also position. After that for the next 300 start breathing harder than you think you need to, and this is for two reasons. First, you are sucking in more oxygen than your competitors while they're going into oxygen debt. You do this because you are preparing for your kick. The second reason is that with you breathing hard, your competitors will think you're dying, while actually you're preparing to kick their butt. For the last 300, get yourself in position for your kick. It is okay to wait for the last 100 to pass everybody rather than run in lane two on the last turn. Congratulations in advance for your victory.
Remember, the winner isn't the guy with the most miles or the most leg speed or the most experience or the best time. The winner is the guy who gets to the finish line before all the others.