I've watched this TED talk several times now and I find it really inspiring, persuasive, and informative. Meg Jay explains three things that every person in their twenties should know:

1. "Do something that adds value to who you are. Do something that might be an investment in who you might want to be next... Don't discount 20-something exploration, but do discount exploration that's not supposed to count. It is not exploration; It's procrastination. Explore work, and make it count.
2. "New things come from what are called our weak ties: our friends of friends of friends... Half of new jobs are never posted, so reaching out to your neighbour's boss is how you get that un-posted job. It's not cheating; It's the science of how information spreads."
3. "The time to start picking your family is now... The best time to work on your marriage is before you have one. This means being as intentional with love as you are with work. Picking your family is about consciously choosing who and what you want rather than just making it work or killing time with whoever happens to be choosing you."

In short, "30 is not the new 20, so claim your adulthood, get some identity capital, use your weak ties, pick your family. Don't be defined by what you didn't know or didn't do. You're deciding your life right now."