The old adage that "time is money" is categorically true, but for self-employed workers, it is a fact of life.

"Time is money"--or, more to the point, "time is income"--is something they must constantly think about. Any consultant or worker who charges clients by the hour lives this reality on a daily basis, and even part-time workers who are dabbling in the on-demand economy know how valuable a resource their time can be.

However, the issue of time as it relates to gig-work is wrapped in the concepts of flexibility and income. A recent study conducted by Emergent Research and my company, Intuit, found that 60 percent of those who choose on-demand work do so because they are looking for a flexible schedule.

Of course, that flexibility can quickly wash away if you start working 80 hours a week.

So how do you maximize your income while hanging on to the flexibility that drove you to on-demand work in the first place? The answer is time management.

Here are three tips to help you better manage your time when you're working for yourself:

1. Get organized and stick to it

If it feels like time is consistently slipping away from you, organization might be your issue. Make sure you have a good calendaring system in place where all of your personal and work-related activities are captured.

Most importantly, stick to it.

If your photo shoot or drive time is only supposed to last 4 hours, don't run over your time and shrug it off. And, in the event that something does run over, recalibrate so you can get back on track sooner rather than later.

By staying on schedule, you'll learn to separate your work time from your personal time, and maximize your output in the process. This will make your work more productive and your free time more enjoyable in the long run.

2. Prioritize

The toughest part about managing your time is deciding what to do when a scheduling conflict arises. After all, you can't be in two places at once.

You need to approach your work knowing what your priorities are.

If your priority is to spend more time with your children, then maybe you should consider scheduling your work during school hours. Use the incentive of family time as motivation to power through your work.

Or, if a current priority is to earn extra cash so that you can pay for an upcoming trip, maybe you temporarily plan to work a few extra hours on Saturday and Sunday. If you treat your priorities as a compass to guide your work schedule, you will be happier with your work-life balance.

3. Find helpful apps

There are several tools and platforms that aim to minimize your non-revenue-generating work. There are apps and websites that exist to aid with finding work opportunities, scheduling, accounting, project management, and much more.

For easy real-time messaging and file sharing, I suggest Slack. Similarly, Basecamp is another great collaboration tool specifically for project management, to-do lists, and file storage.

If you need to send, sign, or approve documents, DocuSign will make your workflow simple, secure, and fully digital. If you run a customer-based business, it can be hard to handle customer service on your own--that's why there are tools such as Zendesk.

And for finances made simple, I'm practically required to suggest a tool from my company, QuickBooks Self-Employed, which makes it easier to manage business and personal finances, track mileage and send invoices.

These tools are all designed to help you be more productive, letting you spend more time actually doing what you excel at--whether it be photography, consulting, driving, or developing--and less time managing administrative tasks.

The bottom line is that time is a self-employed worker's greatest asset and most important resource to manage. You must respect your time and schedule in order to find happiness and success as a self-employed worker.

If you can be honest with yourself about your time and find efficiencies to support your workload, you'll be able to spend more time doing what you love and less time worrying about what you don't.