>>78074795There's really not a lot to it, being older than them is already your biggest advantage. They think mundane shit like going to college, having your own car, living in your own place, or having been to Europe is exotic and impressive.
Other than that? Make them laugh, listen to their dumb problems and offer advice but don't pry too much, make it clear things won't last forever, hype up college and adult life for them to look forward to, and when it comes to sex let them explore at their own pace.