As was mentioned before, be sure to get plenty of cutaways. You never know when you'll need them.
We have a half-hour show after our 11 every Friday night. The show is about not just the game, but all of the other aspects as well. From the band, cheerleaders and fans, we shoot it all. I only shoot two games a night, and we have about seven or eight other guys out as well, each getting two games. If you want decent stuff that actually can be deemed 'highlights,' than two is the max that should be asked of a guy. Anything else, you're running worthless blocks and if you're lucky, the occasional TD.
Shoot from up top? Not if you want the blandest vid ever shot at a high school game. If you can't shoot from field level, don't shoot it at all.
Granted, I'm shooting D-1 college and NFL every week, so I'm used to the stuff.
As for shooting techniques, I rarely can use shutter on a Friday night. No 2X, either. If you've got a HS field that's that bright, let the camera eat it up. Too much DOF for HS stuff is never a problem I've seen. If you've got a decent camera, WB on 1 or 3 should be OK. 95% of the time you'll get a good WB on 1, but there are stadium lighting configurations that are more towards 5.6K.
I don't mean to be harsh. I just call it as I see it.
Good luck out there.
And if you're hit, be sure that you're rolling. It makes great vid to show the rookies...