Starting my first business was one of the scariest decisions I'd ever made. I was a very young man with a very young family. I'd dropped out of school and moved back to my home state because a misunderstanding had led me to believe it would give me a competitive advantage.

Instead, I began like anyone else, looking for clients anywhere I could find them and taking any job that came my way. I worked long hours, lived on next to nothing, and spent more nights than I care to remember tossing and turning in fear that everything would fall apart around my ears.

It didn't. Gradually, my business stopped looking like the jury-rigged dream of a naive kid and became a thriving enterprise. It's impossible to attribute the transformation to any one cause, but the following three rules were critical to my success:

1. Do what you're good at.

When it comes to career advice, I personally find "follow your passion" a little cloying and naive. American Idol taught us that a passion for singing is more a burden than a blessing if you can't carry a tune; the same remorseless logic applies to business.

Prioritize aptitude over passion. What are you good at? What kinds of problems are you eager to solve? In my experience, passion comes when you gain mastery over something difficult. 

Starting a business will take most of your time, so it's important that you actually like what you do. Your fondness will sour fast, however, if you don't actually do it well. Choose a business that checks both boxes--something for which you have both a liking and a knack. 

2. Don't quit your day job.

It's exciting to think of leaving your 9-to-5 in the rearview mirror as your fledgling business carries you speedily toward an exciting future. In reality, it'll probably be a while before you're profitable enough to pay for rent and groceries. 

Hang onto that steady paycheck until you're sure you don't need it. If nothing else, you can invest the cash into your business and watch it grow that much quicker. 

For example, I opened my first business repairing commercial signs when I was 23 years old but continued working part-time at another sign company while trying to drum up customers and learn the ropes of full-time entrepreneurship. 

It didn't last long--my boss fired me as soon as he realized I was serious about leaving to start a competing business--but knowing I had a steady source of income during those first uncertain weeks was psychologically invaluable if nothing else. 

3. Fake it like a pro.

Not all cliches are equal. If "follow your passion" should be taken with a grain of salt, "fake it 'till you make it" should be hung on every wall and pondered daily. 

Starting your own business is like jumping into the deep end of a swimming pool. You feel out of your depth because you are. You quickly discover that what passes for swimming when your feet can touch the floor is really just splashing around. Now you have to learn to swim for real.

I remember this well. I used to take calls from prospective clients in the kitchen of my tiny apartment. I'd answer the phone using a fake voice, ask the caller to please hold, wait for my pretend secretary to transfer the call to my pretend office, then jump back on the line with a hearty hello as if I'd been doing this for years instead of weeks. 

Fake it 'till you make it means acting like the real deal regardless of how you feel inside. Everything about your new business should come across as authentic, from the way you present yourself to the quality of your business cards.

Be professional and courteous with customers and competitors alike. Work your butt off every day and continually educate yourself about your trade, whether through online courses or with a library card. 

Eventually, your inside will catch up with your outside, and faking it will be a thing of the past. You'll wonder why you were ever afraid of the deep end of the pool to begin with. Your business will thrive, and you'll be ready to move on to the next challenge.