(FORTUNE Magazine) – There's a natural tendency to want to get bigger--and whenever possible, to do it quickly. But when it comes to companies, impatience for growth can be a dangerous thing, pushing CEOs to take chances that don't make sense. So this year, as we zeroed in on the companies that have soared with speed, we also searched for ones that have done it right. The six lessons that emerge may help as you set off on your own path to smart growth. Indeed, seven of the companies on our list have so much potential, we think their shares are worth buying.