You need to aim beyond what you are capable of. You must develop a complete disregard for where your abilities end. Try to do things that you're incapable of... If you think you're incapable of running a company, make that your aim... Make your vision of where you want to be a reality. Nothing is impossible.
We are all advertising, all of the time. If you want to sell your car, what do you do? You clean and polish it and make it the best you can. Some people bake bread when they are trying to sell their house because the smell adds a friendly feeling. Even the priest, with all his or her fervour, is advertising God. Everybody is selling.