I think what had the most effect on me was not any one book, but the hours and hours I spent at the public library as a kid. Librarians took a friendly interest in me and recommended books for me to read. My mother the JW had no idea of what I was reading as a kid and teenager. It all sank in and eventually surfaced again when I left the wtbts. My recommendation is to read a lot, especially history, science, biographies, literature. What I am now comes more from the books I read than the effect of the wtbts.
If you know any kids you want to help, take them to the library every week and let them choose any books and as many books as they want to read.