5 Things Every Startup Should Know You can learn now from what these entrepreneurs wish they'd known then.

At the tender age of 19, Rob Rohn and Dan Mermelstein started selling aftermarket auto accessories from their college dorm room. Ten years, four locations and 23 employees later, Gilbert, Ariz.-based Vivid Racing is a $10 million business.

We asked Rohn and Mermelstein, both 29, to share a few of the business insights they wish they'd known when they were just starting out in 2001.

1. Focus. "Know exactly what type of target market and demographic you're trying to reach. By knowing that, you'll really be able to focus on the direction you want to take."
   
2. Different is not enough. "Originally, we [tried] to make sure we had unique products, items that not a lot of people could get their hands on. But we've learned that even with unique products, customer service is still what makes a huge difference. People are deciding whether to spend a large chunk of money with your company--or with another. What's going to make that difference? Good customer service."
   
3. It's who you know. "There are so many businesses out there that are ready to take advantage of a startup company or someone who really doesn't have any idea of what they're doing. Get quality referrals from people who have been there and are positioned where you want your business to go."
   
4. Hire smart. "Employers should do thorough, multiple interviews and background checks [on potential employees]. We've had more than 100 employees since we started, and some of those turned out to have criminal pasts or [just] shouldn't have been working for us."
   
5. Get some type of management training. "Entrepreneurs are usually do-it-yourself types, and as you start managing and directing employees, it becomes harder and harder to get your own work done. You start micromanaging, and you lose focus."