1.Never ever give personal gaurantee for more than your net worth! So that failure stops with you, otherwise your entire family gets affected.
2.Focus on one thing , become incredibly good at it.
3.Focus on customers and trust yourself on giving value , customer insight is better than customer need.
4.Be alert about interest on debt ,business debt ( high interest) essentially will kill every possible way of being rich, instead it will drag you down the road of no return.its 100 times better to get VC fundin or investor money than business debt.VC will stop you before it's too late. LESSON ....take business debt only from banks if it's low interest, then investor money. Ideal is do business with customer money if you are in software. Get pre- sales before you make, it's tough but it works.
5.Indecision killed most of the profit for us,we were two people protecting each other back and it doesn't help, when you are in such impossible situation and indecisive,we should have closed the business 2 years earlier. It would have saved us a lot money and time.
6. Always have 3 extra advisers on board if you are just two co-founders....to get a perspective otherwise emotions run high and it will be huge drain on the company.