LearnVest founder Alexa von Tobel took a lot of risks on her way to building an online financial planning start-up recently valued at $100 million. She dropped out of Harvard Business School at the height of the financial crisis, motivated by a passion for a simple, disruptive idea: to turn financial planning into an accessible, affordable Weight Watchers-like system that provides clients with answers and alleviates their worries.

Von Tobel learned something important along the way, a piece of advice she now gives small business owners: don't think so much about the business that you forget to protect yourself. Here are von Tobel's recommendations for how entrepreneurs can build their business without sacrificing their personal finances.

1. Don't invest too much of your own money. One of the worst things you can do is to take on so much risk that you can't think clearly. If your primary concern is losing your house if you business fails, you're not going to be in a steady position of power, which is where you need to be when you're running a business.

2. But be sure to invest some of it. Von Tobel started LearnVest out of a tiny savings account she used to pay designers and technologists. "Because I was paying for things myself, it sharpened my focus of how to spend money," she says. If someone gives you a million dollars to start a business, you're going to care a lot less than if it's your own money and you have some risk. You need skin in the game.

3. If you've never climbed Kilimanjaro, find investors who have. Building a company is like climbing Mount Kilimanjaro. It's so hard and arduous and a few rocks may fall on your head. "I want money from people who have climbed Kilimanjaro, so I can say, "What did you pack? What season did you go? What did you wear? What were your blind spots? How did you train?" von Tobel says.

4. Know the risks. "When I started LearnVest, I had to know the risks," von Tobel says. "I needed to know the worst-case scenario." Von Tobel had enough savings to fund the start-up for exactly nine months. If after nine months, which she called that "Cinderella moment," the company hadn't made progress, she was going to have to go back to business school.

5. Have a solid financial plan. Having a financial plan is even more important when you are an entrepreneur. You need a road map to know what you're going do, showing everything from an employment contract to your emergency savings. For sole proprietorships, LLCs, and limited partnerships, you are running the finances through your own tax return, which means that you could be liable for a lot more than you think.

Remember if your business goes under, so do you. Be sure you are aware of what that means and how to protect yourself.