Secrets to success?

 Bill Gates tweets advice for new college graduates.
What would Bill Gates do if he were starting out today? The world's richest person offered new college graduates some advice Monday on Twitter.

Gates, the co-founder of Microsoft who stepped down as CEO in 2000, delivered a virtual commencement address in the span of 14 tweets.

"New college grads often ask me for career advice," he began. "Looking back on when I left college, there are some things I wish I had known."

For starters, Gates said he would get involved with artificial intelligence, energy and biosciences -- "promising fields where you can make a huge impact."

That includes tapping into renewable energy sources like solar and wind power and automating factories, construction sites and retail locations.

"It's what I would do if starting out today," said Gates, who has an estimated net worth of $87.6 billion, according to Forbes.

He expressed one regret. "When I left school," Gates said, "I knew little about the world's worst inequities. Took me decades to learn. You know more than I did when I was your age. You can start fighting inequity, whether down the street or around the world, sooner."

But Gates also expressed optimism that "the world is getting better."

"Sounds crazy, but it's true," he said. "This is the most peaceful time in human history. That matters because if you think the world is getting better, you want to spread the progress to more people and places. It doesn't mean you ignore the serious problems we face. It just means you believe they can be solved."

Gates concluded, "This is an amazing time to be alive. I hope you make the most of it."