"If you think you can, or you think you can't, you're right."
I cannot tell you how many successful entrepreneurs I've talked to love that quote from Henry Ford, the man who created the Ford Motor Co.
You understand why they do.
In a world where everyone has access to the same resources--talent, financing, technology, and the like--often whether a new business idea works depends on someone's attitude, determination, and stick-to-itiveness.
In other words, it often comes down to thinking whether they can or they can't.
Starting anything is difficult. Going into it with less than a positive attitude is like handicapping yourself. You are making your life harder than it has to be. And you simply won't have the necessary drive and desire to overcome the inevitable obstacles that are going to pop up.
Worse, it tends to be a self-fulfilling prophecy. When those (inevitable) problems crop up, you say (maybe subconsciously), "See, I knew this was never going to work. This just proves it." Your energy and your commitment flags, and things get worse from there. You work less hard ("what's the point?"), and eventually you just stop.
You don't think you can, so you don't.
Conversely, if you think you can, those setbacks are treated like the inevitable bumps in the road they are, and you keep going.
There's an old joke that sums this up perfectly.
Two shoe salesmen are sent from U.S. headquarters to open a new market in a developing country.
Salesman No. 1 files this report: "The situation is hopeless. There is no one to sell to. No one wears shoes." (You can guess how successful he is. Right? Not very.)
Salesman No. 2, sent to the exact same area, files this report: "The situation couldn't be better. No one here wears shoes. I can sell to everyone!"
It is people with that second attitude who tend to succeed.
Be that second person.