Here's a [growing] list of things I've learned so far in my 20's:
1. Nobody Knows
If you don't speak up, nobody will hear you. If you don't introduce yourself, no one will know you. There are no more "class introduction" days. There are no more teachers to call on you even when you're shy. The real world is a scrappy place, and it's on you to make yourself known.
Your time is your most valuable commodity. Everyone will try to take it from you. Bosses will ask you to stay late. Friends will ask you to come out. Parents will tell you to call more. Siblings will want to Skype. Significant Others will want you to spend a little more time. Time is all you have, and your time is going to go fast. So spend your time wisely--even if that means getting greedy with it.
3. Get To Grinding
It's 2016. We have the Internet and it has matured vastly since the 90s. If you're tired of your job, quit. If you want to start your own company, do it. If you want to connect with someone across the world, you can. If you have a dream, pursue it. There are no more excuses. Every tool you need is right here. Get to grinding.
4. Stop Trying To Figure It Out
The 20s syndrome is everywhere. Most 20-29 year olds (and many even after that) spend all their time worrying or wondering who they're going to be. Who they should be. Who they're going to become. Meanwhile, they miss moment after moment to practice skills and learn what they need to learn in order to become that "future self" right now, today.
Nobody is going to wash your dishes. Nobody is going to clean your apartment. If you don't pick that piece of pepperoni up off the floor, nobody else will, and it'll sit there for as long as it takes you to do the deed.
6. Make Good Choices
It sounds cliché, but the people who become "successful" in the 30s are the ones who made good choices in their 20s (usually). For some it takes longer to figure out than others, but at some point you're going to have to call it quits on the Thirsty Thursdays, you probably shouldn't binge-watch Netflix for 72 hours in a row (unless dying of sickness), and you should work to surround yourself with people who inspire and motivate you, instead of those who settle and stop improving. This is the hardest part for most people--knowing when to let go and move forward.
7. Develop Your Talents
This gets taken so much for granted, but it's far easier to learn something in your 20s (especially when you're motivated by your lack of funds), than when you're moderately comfortable and in your 30s, or 40s, or 50s. Spend your time learning and harnessing your skill-sets.
8. Learn To Manage Your Money
This is something nobody teaches you in school, and its sort of on you to figure out. (Personally, I reached out to family friends who I knew were investors/traders and asked them to kindly explain to me the basics--which they did, willingly.) This means opening up an IRA and putting in 10% of every paycheck. This means paying your taxes. This means withholding the urge to spend money frivolously so that you can save for something more important. Learn the skill of saving and money management now, because it's only going to get tougher.
9. Build Your Network
Now is the time to build your network. Everyone your age is struggling just like you. They're all broke, like you (even if they appear not to be). Find the ones who are passionate about what they do and connect with them. These are the people who will be successful 10 years from now, and just like how you would invest in an early start-up, invest in your relationships to keep doors open in the future. Remember, your net worth is your network.
I'll speak for myself here in that some days I feel like I'm moving so fast that I can't see what's going on around me. I'm so focused on where I want to go that I start to tunnel-vision, and I forget that my 20s are also meant to be enjoyed. These are the young years. We're full of energy. We have big dreams and see no reason why they can't become our reality. To my fellow peers, remember to take time to enjoy yourself and bask in the fact that you are still very much a child in the world. Stop saying you're getting old. Stop thinking you're "all grown up." You're not. You just got out of tutorial mode (school) and you JUST stared playing the game of life. You have the rest of your life to "be an adult." There's no rush.