I'm in an interesting situation. As a community college librarian, I've been providing IL one-shot classes for years. I had not had the opportunity to work with the school librarians or do any direct outreach to the high school students.(Though we used to be a public/college joint-use library, so I did work with individual high schoolers.)
However, in the last few years, our campus has started an Early College High School, where public school students enroll for 5 years and graduate with a diploma and an Associates degree/2 years of college credit. I have found that my normal methods of teaching the college students don't work as well for teaching high school students, especially freshmen. I'm very interested in what other academic librarians have done when working with high school students. I have met with the media coordinator at the nearby high school, but would love more ideas.
As for my own experience, I have taught several one- or two-session classes to the freshmen study skills classes and learned several things that others might find useful.
1. My usual presentation style of talking about a resource, then showing them how to use the resource, then letting them use it on their own for a few minutes, bores them very quickly. And once they're bored, they tune you out or start talking to each other. I've added more visual elements to my presentation, an activity that involves making them move around, and tried several reinforcement/quiz activities (like
Jeopardy Labs. I use some of these with my college classes now, as well. I'm looking for more activities to add.
2. If you can find a way to engage them, get them talking, they will talk. I usually have a much easier time getting my high schoolers to interact with me than my college students. Next time, I'm going to try a group activity that gets them talking to each other. Interestingly, they are also much more responsive on the session evaluations I give out, actually giving me constructive criticism. My college classes rarely do that.
3. Be very clear with class objectives and don't try to cover too much. This is good advice for any IL class (which I struggle to follow), but it seems to be particularly important with the high schoolers. The college students seem better able to handle a little rushing if I start running out of time. I work with the class instructor to find out what is most important for the students to know.
I hope others respond to this thread, because I am very interested in finding out what strategies others are using with respect to high school students. There's not a lot of research out there that I've found, and I have looked! One article that may be of use is
"Navigating to Information Literacy: A Collaboration Between California High School and College Librarians." by Dawn Dobie, et al. CSLA Journal 34.2 (2010): 6-9. (Available via Academic Search Premier.)