One aspect of building a succesfull business that is often overlooked is that a failure earlier in ones career can be helpful. People here talk of solid foundations and experience, but what they mean is they have been going over ten years before they make a fist of it. By objective standards that's failure, or at the very most modest success.
I think modest success is one of the worse things that can happen. You think things are okay and you never really know things any differently. I have failed at a few things, it's a bitter taste, and it seems that it has no use. But it does because the next time you intend, and sometimes succeed in doing things so much better.
A good example is a guy who posts on here. He was a window cleaner for many years and thought himself a success, but had a disatisfaction that he could do better. Anyone telling him how to run or improve his business would have been met with a short sharp responce.(I draw your attention to some of the replies of the experts above)
He sold his wc business and started another in a different field entirely. He failed at this and it hurt. He gave this new biz everything he had and it broke his spirit. He was skint, he had failed, but he had also learned some new approaches, approaches that if they had been broached with him whilst he was running his semi successfull wc biz would have met with the aforementioned sharp responce.
He started wc again. Humbler, no preconceptions, but fiercely determined to succeed. He has, and how.