1. Writing a play was an interesting experience that got me thinking a lot about how to express ideas through the words of my characters. The dialogue-based nature of the play allowed me to cut straight to characterization, plot, and theme, without worrying about the tone of narration or elaborate sentence structure. This makes it more concise and direct than most things I write, and it was easier to spill out onto a page than a formal essay. I certainly felt the limitations of the stage as I was writing, however, and I had to keep resisting the urge to make my setup really complicated. It turned out well, I think, but sometimes it felt like I was battling against the format rather than embracing it. I really enjoyed being able to speak through my characters, and I've learned some things about dialogue that I can apply to other forms of writing.
2. My advice to a child (at whatever age he/she could first appreciate good advice) is to always question your assumptions. Whenever I'm wrong about something, it's because I'm assuming the wrong things and making bad conclusions based on it. If you realize what you're taking for granted, you can get a much better perspective on things. I can especially see this with respect to politics (though that's not something that the advice-receiving kid should worry his little head about). When I first started thinking about political stuff, I had automatic assumptions about what is "good" and what's "bad," and this made me wonder why politics was so controversial--the answers seemed so obvious. And they're really not. Half of my political views have been completely reversed since then. So when forming a philosophy about life, it's important that you don't make too many assumptions about what you want or don't want, and that you think about the way you're thinking.
3. The longevity of literary works is something I've been wondering about, actually. I think the works that last are the ones whose messages are powerful enough to be applied to any time period, not just the one they are written in. Les Mis doesn't only speak to revolutionary France, for example, and 1984's message applies equally well to 1985 or 2020. This brings up the question of which of today's literature is going to survive as long as these other works. Nowadays, when a book is popular, it's because of a flashy advertising campaign (cough eragon cough), or because it gains a pop culture fan base (like Harry Potter), and neither of these things last more than ten years or so. Lots of great things are being written, but they're usually focused on the modern era and play off of hype from current events, so it's uncertain whether their messages can last. That said, my writing will live forever--as long as I write it on stone tablets and bury it for a future civilization to dig up. I'll be famous, it'll just take thousands of years for the fame to sink in.