Oh, and if you run in formation, TRY your best to be in the front. The guys running in the front have it easier... for one you don't have to worry about kicking the feet of the guy in front of you (sometimes becomes an issue if you or the guy in the front get real tired), also you get good fresh air, instead of smelling sweat and breathing air heated by a bunch of sweaty dudes. Also, dealing with stragglers doesn't become an issue.
I remember at MOS school, we had to go to an Army one because of our MOS, us Marine guys volunteered to carry all the heavy equipment and volunteered to be at the front. Turned out it's so much better to be at the front that it means carrying a bit more, it was actually worth it.
Yeah, formation running is horrible for improving your time. It's just something to get your engine on and humming.
Hill workouts are good, but it's not a very good measure of time. Also, DO NOT run down hill. The amount of pressure that you put on your knees by doing that can be a short cut to a knee injury. I remember back in my cross country days, we'd actually somewhat slow down on the downhills... which we compensated by going full blast uphill.
Just make sure you're doing things consistently.