The Happy Fun Pundit has a list of do's, don'ts and questions to ask. They pick on Sean Penn, but Nicholas Kristof could've used a few of them when he visited earlier this year.
When they offer to take you to the children's hospital, refuse. They always take you to a children's hospital. There is nothing to learn there, other than that Iraq has children, and they sometimes wind up in the hospital. Your time would be better spent staying home and watching reruns of "ER".
Likewise, ignore the baby food factories, the glorious arts and entertainment facilities, and the city's best eating establishment. If you want to be taken seriously, learn to at least recognize when someone is trying to blow sunshine up your ass. Potemkin villages have fooled nitwits like you for decades. By now, you should know better.
Read the whole thing, it's enlightening.