Surround yourself with people who take their work seriously, but not themselves, those who work hard and play hard.
We all hoped in 2001 that we could put in place an Afghan government under President Karzai that would be able to control the country, make sure al-Qaeda didn't come back, and make sure the Taliban wasn't resurging. It didn't work out.
I don't know that there is much the United States can do except work with the international community.