Henry Ford got it absolutely right when he said, "Whether you believe you can, or you believe you can't, you're right."
There are countless things required to start a successful company: discovering the market need; coming up with a product or service that fills that need; communicating successfully that you have the solution that people have been searching for. You could go on for quite a long time describing what you must do to create a lasting enterprise.
And I would not spend a single minute debating with you that some things on whatever list you come up with are not important.
They all probably are.
But the biggest reason people fail is that they never try.
As basketball and hockey players have said forever: You miss 100 percent of the shots that you never take.
People can be extremely risk averse and the idea of a venture not working out can scare them to the point where they never get underway. They keep thinking about the idea or maybe doing more and more research, and so they never pull the trigger.
Or they don't start because their advisers (or spouses) are very conservative and keep pointing out reasons why they should delay, and so they wait and think and refine and tweak and refine some more.
Or they take too long to test the market, putting off actually beginning to the point where the competition has passed them by.
Or they think that just one more bit of market research or one more phone call will guarantee success.
All these situations are sad.
As I have written about before, if you think you have a good idea, get into the marketplace as quickly as you can, using as little money as possible. Take a small step toward your goals, and see what happens.
Maybe you find out right away you have a hit on your hands. (It does happen occasionally.)
Maybe--and this is much more likely--you will learn that the market wants you to fiddle a bit with what you have. (To play with the clichéd example, people aren't crazy about coming by your lemonade stand to get a drink every time they are thirsty, but if you could somehow figure out a way to get your lemonade into the break room at work, they would be more than willing to give you a six-month contract.)
And if your idea doesn't work in any form, you aren't out very much, since you kept the cost of your initial small step toward your goal to a minimum. That means you will have the resources to try again.
But if you don't try, you'll never know.
That's why I truly believe that the biggest thing standing between you and success is you.