I’ve got my own ideas, but I also tapped into the sage wisdom of that modern water cooler known for its critical thinking: Twitter. I told people on Twitter that I’d be speaking to you today, and what would they tell their past high-school-graduating selves? I already had my own thoughts, but I was curious about what other people might say — and I was pleasantly surprised that their ideas were similar to mine. In other words, there’s a consensus on the advice I’m about to dispense. Collectively, I’d say that, combined with the ages of these people, this advice is about 1,400 years old.