The best part about your 20s is that you can recover quickly from the inevitable mistakes you'll make as you figure out how to make it in the real world.
That said, there are some poor choices that have lasting effects, like not starting to save money, that are easily avoidable.
We've sorted through a variety of advice from entrepreneurs and writers on Quora and found recurring themes.
Here are the worst mistakes 20-somethings would be wise to avoid as they establish their professional and personal lives.
High intelligence, natural talent, and degrees from elite universities are all good things to have, but they do not guarantee that you will land a great job - and they mean nothing when not paired with hard work.
"I spent my 20s in corporate environments, and I remember them for working nights and weekends," says Sylvie di Giusto, the founder of Executive Image Consulting. "Sweat, hassle, pain, as well as diligence, perseverance, and an enormous amount of effort and energy characterize my career at this point. I've learned that there are very little short cuts when it comes to career success. Success doesn't 'just happen.' Never."
As you get older, you'll learn pretty quickly you can't party like you did in college. "Your hangovers will be so bad at 28 that the idea of staying out drinking all night will be hilarious to you," Meggie Sutherland Cutter writes on Quora. And the more years out of school you get, the more excessive drinking, smoking, and even an unhealthy diet go from acceptable behavior to dangerous habits.
Communications professor Michael Weston says 20-somethings also need to pay attention to their mental health, since any potential issues usually arise in your 20s.
Mike Nudelman/Business Insider
Don't let retirement feel too abstract and distant.
Entrepreneur Aditya Rathnam says there's no need to start investing too much, since you're just starting out, but it's essential to take advantage of your company's 401k matching program, if one is available, and/or open a Roth IRA account.
Prestige and a fat paycheck can certainly make you happier, but there's plenty more to success than that, says Joe Choi on Quora.
You're setting yourself up for years of regret if you pursue a paycheck rather than your passion.
Ending a serious relationship, getting fired from a job, and having your startup crash and burn can all seem devastating when they happen to you for the first time. But rather than giving up or aiming for a lower target the next time, you should use failures as opportunities to learn and improve yourself.
"Getting fired and waking up the next day as usual made me realize that failure isn't the end of the world," says Quora user Carolyn Cho. "Getting dumped taught me the difference between a good and a bad relationship, something I already knew inside but refused to accept until the bad relationship was over."
When you're starting out in your career and unsure of which direction you want to head in, you can be susceptible to letting others choose your path for you. It's why "Shark Tank" investor Lori Greiner tells every entrepreneur she works with to never let others' opinions influence them on a personal level.
"Your success will have everything to do with how you perceive yourself, because how you perceive yourself is how others will perceive you, too," Greiner says.
You don't need to be a married homeowner with a 10-year career plan by the time you're 30. Be patient, and stay focused on the present.
Matisia Consultants founder and CEO Kristina Roth says when she was younger she felt like she had to achieve all of her goals as soon as possible, an anxiety-inducing mindset that was counterproductive.
"In my 20s, I learned the concept of delayed gratification and that you need to pay attention to important decision points in the tree of life, which will change your life one way or the other," she says.
Friendly relationships with your colleagues can be mutually beneficial, but you will never get along with everyone.
"Inevitably, someone will always dislike you," says Cho. "I wish I had figured this out a lot earlier and stopped trying so hard and worrying so much about it."
"Your college pals that you think will be your best pals for life? Some will still be there at 40; most will be living their lives doing their thing," says Sutherland Cutter.
When your friends aren't all living in the same town, you'll realize which ones mean the most to you and are worth the effort of maintaining a relationship with.
Traveling and living somewhere new can be culturally enriching, and your 20s are a perfect time to do both. But, says Choi, do not think that moving to the opposite coast means you'll suddenly find meaning and direction.
It's important to build relationships with colleagues and others in your industry, but if you stay within the confines of a particular world, you can start to get a myopic perspective. Make an effort to branch out.
"The people you surround yourself with have a direct impact on your success and failure," says Jon Levy, founder of the Influencers. "They will affect everything from how much you exercise and what clothing you wear to how much you earn and what values you deem important. So if you want to live a life full of joy and accomplishment, you need to become masterful at building relationships with good people you respect, and letting go of relationships that have a negative impact."
Author and investor James Altucher thinks that many people in their 20s get caught up in absolutes. For example, some feel like they have to choose between a career path that benefits them or one that benefits others, without realizing that self-interest does not have to mean the opposite of doing good for the world.
Reuters/Edgard Garrido
You won't stumble into a "perfect" relationship. You'll have to work on one.
Some people decide to spend most of their 20s single, unattached to anyone. Others search for the right person to marry. The latter group can get caught up in the fantasy of finding someone where everything just clicks and the relationship is effortless. But in real life, the most meaningful long-term relationships require work and dedication.
"You have to continuously make sacrifices, adjustments, accept shortcomings, explain yourself. But you know what - that's what makes it fun!" says Mitesh Jain on Quora.
"It's hard to predict where you'll end up and what you'll be doing," says Choi. So avoid driving yourself crazy with five-year plans, and focus on immediate goals.
As you're finding your way in the world, determining who you are as an adult and building a career, it can seem like your friends or colleagues are more successful and confident, says Sarthak Pranit on Quora. But regardless of income, job, or living situation, every 20-something is still figuring things out as they go along - and they'll continue that process the rest of their lives.