The key thing in my mind is making sure you have a good range of appropriate yet challenging books for the gifted reader and making them accessible and obvious. These might be books typically shelved with the adults books. Particularly pay attention to books that aren't the most popular, but are still well written and engaging to people of all ages. These exist but take a bit more work and research to find. Perhaps encourage gifted kids that come through your library to write reviews of these books to be posted along a display.
