As someone who has run an early-stage startup, I know what it's like to go to bed each night dreaming of the day you start to scale. You're low on resources. You're short on money. And you fantasize about the growth stage because it means your company is on the path to success.

But once there, you'll find scaling has its own unique set of challenges.

In just six years, ThirdLove has grown from two people working out of an apartment to a company with multiple offices and hundreds of team members. But the strategies that made us successful in the beginning haven't necessarily helped us scale.

To survive, every startup has to streamline procedures and become more efficient--without losing the scrappy, innovative spirit that got you there.

Here are the challenges to prepare for:

1. Moving from a multi-functional team to specific departments.

An early-stage company does best when made up of generalists who can perform many tasks quickly. For example, the person you hire for marketing might also write copy, work on merchandising, and jump in to help with emails.

At that stage, you don't have the resources to hire people who can only do one thing really well.

As you scale and ramp up hiring, the skill sets you look for change. You begin building departments and searching for people who are really knowledgeable in one or two specific areas. I think back to the early days of ThirdLove, when email used to be one-tenth of a general team member's day. Now, we have six team members who make up our email team.

That type of radical change doesn't mean you're simply moving people around within the company. It requires a structural shift.

For example, there are only two people on our team today who were with us in 2015. That's not because the original team members weren't great; it's because the company's needs evolved.

And there are very few people who can--or want to--make the transition from an early-stage startup to a more structured company that is in the growth stage.

2. Developing a process without letting it slow you down.

In the early days of a startup, you're trying to move as quickly as possible and get things out the door.

But as your company grows, you need to set up streamlined procedures to maximize communication and efficiency. That includes figuring out how to share information within the company and to outside partners to keep everyone on the same page.

At ThirdLove, whenever we have a major cross-functional initiative, the project leader holds weekly or bi-weekly meetings with at least one person from each functional group. They address the state of the project and the steps needed to complete it. Then, each representative shares the information with his or her respective team. This helps everyone stay in the loop on different strategic initiatives, even if they're not contributing huge amounts of work.

The key to making any process work is soliciting feedback.

After a new process is implemented, you should personally speak to all the teams to ensure it's working. If something is repetitive or time-consuming, you have to strategize how to rework it.

Just make sure team members know who to talk to if they run into an issue.

3. Becoming too large to adapt.

Startups succeed in part because they're small and capable of innovating quickly. They are the opposite of a slow-moving, massive corporation.

It's essential to stay scrappy as you grow, to keep your original passion and ingenuity intact.

One way to do this is by creating workable versions of big-company practices. Larger companies have established processes that work really well--about half the time. For the other half, those processes are time-consuming or even counterproductive. But you can use a lightweight version to accomplish a goal without slowing your team down.

Think of how companies prioritize product features on their roadmap. Large companies usually give the product and engineering teams weeks or months to analyze and make projections. But that type of prolonged analysis doesn't work for startups. In fact, most early-stage startups don't even hold prioritization meetings at all.

As you scale, financial assumptions and projections are needed to make better decisions about product features. Make it quick and dirty. No more than an hour spent on analyzing each feature.

The process may not be as comprehensive, but it provides enough structure for you to move forward. It strikes a balance between the hectic early days of a startup--when you're flying by the seat of your pants--and the rigid nature of a corporate entity.

And that's really what you're looking for as you scale. It's a combination of what made you successful in the past and what will make you as efficient as possible going forward.