Stay grounded in reality! Build your start-up one step at a time with clear goals and detailed steps on how to achieve them. Don't waste your time talking about how you want to change the world when you have not even figured out how to stay alive in the next 3 months. Don't set goals that are so big that you cannot realistically achieve it in any given time. Set goals to solve your immediate problems and work out practical ways to fulfill them. When you have clear direction based on these goals then start working your butt off to get them done. As your start-up grow, your goals will naturally become broader because you will now have more resources such as money and manpower to achieve them. With this approach, changing the world is a natural progression of your growth and no magic is required in between.