1. There are no set truths in business.
2. Learn some basic accounting/finance. For example, you should know the difference between equity and debt or the difference between Net Income and Revenue.
3. https://www.ycombinator.com/library
4. https://a16z.com/
5. Start reading more financial news (Bloomberg, CNBC, WSJ, FT)
6. Find successful founders/CEOs you admire and watch their interviews.
7. Work on something that has great potential rather than an area that is too small or secularly declining. "When a management with a reputation for brilliance tackles a business with a reputation for bad economics, it is the reputation of the business that remains intact."