Developers to Entrepreneurs, How did you do it?

I have been a Software Engineer and a wannapreneur for the past 4 years. I want to finally make the leap this year and start something. It's hard for me to think in business, every time I come up with an idea it's easy for me to sketch the architecture and system design than figuring out the business aspects of it.

• Was it hard for you to make this switch?
• How did you switch gears and made the transition?
• What mental models helped you to think like an Entrepreneur than an engineer?
• How did you do it?