The easiest way is to start subcontracting. It's easier to start saving money, and sometimes, you'll hit on a project where you spot a business opportunity.
For instance, you learn the ins and outs of a particular industry, and suddenly spot a niche product. I haven't made the leap yet, because I like the subcontracting so much. But I've spotted many (perceived) opportunities.
I'll give you an example. I once did an Android app for a conference. However the data model was so generic that it basically could've been reused for any other conference. If you're motivated as such, the whole thing could very well be an excellent opportunity to sell a product, instead of one single month of subcontracting.
1. As a contractor, you can work on shorter term projects, so within couple of years you will be get familiar with a number of problems and situations,
2. If you are an engineer who cultivates business mindset and focus on understanding and solving clients’ problems, you will ask right questions, and be able to communicate to them how you see their situation and how you can help. Potentially, they will see you not like a coder, but like a problem solver, they will trust you more, will be more confident in your decisions, tell you more about their business, give you more work.
If you focus on being a business oriented, learn a bit of marketing, product management, speak their language and terminology - in couple years, you will accumulate good understanding of problems and solutions, have connections and ideas.