Once you get introduced to some of the local guys, find a referee/crew chief and ask if you can accompany them to home and away varsity games next fall. This is great experience where you can sit in on pre-game, half-time and post-game talks as well as walk the sideline during the game. There is no substitute for experience and this is a great way to get some. We "adopted" an official last year and he has already done some varsity games this year.
Keep coming to this forum and the NFHS Forum to absorb as much as you can:
NFHS Forum: Football
Find out when there are camps/clinics next spring and summer.
It's a great hobby!