Because mythologies are important to my work, I often favor a kind of mythic voice typified by elevated language, broad strokes. I do try to create and fill in brief scenes or skits so that the reader can witness the story as it occurs. I try to provide available detail such as biographical or historical data but am as likely to present such information for the purpose of debunking it. One of my concems as a writer is how we know what we know and who says so. Since I've never worked with young people, the only advice I can offer is probably fairly standard.
Writing is a process of study, examination, experimentation.
And keeping a journal or working notebook is a good way to begin thinking through projects. Years of dedicated reading, study and research is the best beginning I know. Having a good writing mentor early on is a big plus.