Carter,
ANY race should be only for fun, whether you're racing Beginner or Expert or whatever, whether it's your first race or you've been racing for years. Focus on finishing the race (although 7 miles should be OK), you can't imagine how many things can go wrong during that time. And don't start too fast but at a good pace. Warm up well before the race, but don't go crazy there.
On the trail, be courteous. If you feel someone is behind you, ask if he wants to pass, or if you're out of breath just keep going at your pace, he'll pass you later, there's plenty of time for that. Same thing if you're passing someone, don't yell at him, tell when you're about to pass and if you can't, wait. That'll give you some time to gather strength and pass another time. If you dab keep going on foot on the side of the trail so that people still riding can have a chance. And there's nothing wrong with walking some sections, better that than crashing and being med-evaced.
Last thing, don't fall. Easy to say, but you're actually making up time uphill, not downhill, not on the flats. Additionally, it's not worth taking too many risks, the winner gets a medal and at best a hat or a flimsy T-shirt...
Ringwood is a nice course, although usually muddy and slippery. The last mile or so is a killer. If you've kept enough strength it's a place where you can make up a lot of time.
Good luck and have fun !
Maurice