It takes more than a big idea and a thorough business plan to start a new business. Most entrepreneurs aren’t quite sure what else it takes until they’re well underway, and many are shocked to discover important elements of startup success that they simply hadn’t considered at all.

To find out what startups learn they really need but never though of, we asked eight successful young entrepreneurs from the Young Entrepreneur Council (YEC) for their input. The results may surprise you as much as it did these startup founders:

1. Adaptability

During the early days of our startup, we were bringing on people with very specific experiences and skill sets who had previously worked at larger organizations that were more structured and reliable. We soon realized that a better fit for us was to hire employees who were highly adaptable and open to – and able to – constantly change their roles and responsibilities depending on the needs of the business. The people who thrived and really made a significant impact to the success of our startup were those who could evolve and roll with the punches. They were comfortable with the relative lack of stability that you typically experience at a startup as it begins to ramp up. Ben Rubenstein, Yodle

2. The Ability To Say “No”

Many startups focus intensely on growth—sometimes to a fault. When I dove into real estate, I found myself exploring and experimenting with every possible revenue-generating activity. At the time I thought I was being thorough and productive, but I was really straining our company’s resources and physically draining myself. While it’s extremely important to experiment, every company should have a clearly identified core focus and mission. This helps you analyze opportunities that arise along the way and decline those that aren’t best aligned with your goals. It took me a while to realize it, but saying “no” is equally as important as green-lighting certain initiatives. The most productive, and ironically, sustainably innovative businesses I know are also very good at saying “no.” —Kent Healy, The Uncommon Life

3. Logistics

After raising our angel round of funding, my company decided to greatly increase our marketing and advertising spend. We sponsored 11 conferences throughout the year in major cities across the US. I tried to organize everything myself, but scheduling flights, hotels, car rentals and sponsorship passes was an absolute nightmare for me. Luckily, the account manager on my team was very organized and loved logistics. He took the lead and turned my nightmare into a happy dream. I focused on closing client deals while our new logistics and operations manager took care of all of the logistics. —Jun Loayza, Tour Woo

4. Implementation

There’s no shortage of great ideas and vision in the excitement of a startup, but without implementation, it falls flat! Having a team in place and members who excel at follow-through and implementation is key to taking the vision and putting it into action. Most entrepreneurs are quick starters and big dreamers, so details become tedious and bothersome. If you’re not strong at follow-through, partner with a business manager or create automated systems that ensure things get done! —Kelly Azeved, She’s Got Systems

5. Avoiding Growth For Growth’s Sake

When my partner Lev and I grew to #24 on the Inc. 500, we did it by growing for growth’s sake, not smart growth. Any revenue-generating opportunity we came across, we automatically said, “Yes!” The end result was a massive collapse of the company in 2009. However, through sheer effort and tons of luck, we managed to save it at the last second. Lesson learned: never grow for growth’s sake. It’s critical to slow down, take a deep breath, and ask yourself if your company can honestly support the strain that comes along with that new revenue stream. —Seth Kravitz, Technori

6. Time Management

I know, it sounds boring. But as an entrepreneur, you are naturally dealing with limited resources, and you need to maximize your productivity. Specifically, you need to prioritize your activities so you are focusing your time, money and energy on activities that will bring you closer to your goals. If you don’t have a system for managing your time effectively, youíre squandering your most precious resource. If you want some great productivity tips, check out the book, No B.S. Time Management for Entrepreneurs by Dan Kennedy. —Pete Kennedy, Main Street ROI

7. Sales Is For Everyone

When starting a business, it is quite easy to put different hats on your team—“I will be sales, you lead our tech, she’ll be marketing and he’ll be in charge of operations and administration.” The reality of startup life is that everyone needs to build skills in selling the idea. This does not mean that each employee should treat every person they meet as an opportunity for a cash transaction. However, when you are involved in a startup, every person you meet might be of value, whether as a customer, adviser, partner or simply a brand advocate. Knowing your idea and being able to discuss it clearly and passionately will help the business uncover critical resources from everywhere. Every team member’s informal development plan should include a goal of improving communication and sales. —Aaron Schwartz, Modify Watches

8. Don’t Ignore Your Health

This might sound silly, but hydration is super important to keep my mind strong while in startup mode. We are all attached to our desks, cranking away on computers, and in business meetings. When do we have time to drink water? I’m serious—sometimes our health is ignored in our business, but in fact it enables our personal and business health. Stay hydrated!Erica Dhawan, Erica Dhawan Inc. and Galahads

The Young Entrepreneur Council (YEC) is an invite-only nonprofit organization comprised of the world’s most promising young entrepreneurs. The YEC recently published #FixYoungAmerica: How to Rebuild Our Economy and Put Young Americans Back to Work (for Good), a book of 30+ proven solutions to help end youth unemployment.