Make sure you offend no one by your presence. Remember, you are an ambassador for every other diver in the world while you're there. And make sure you thank everyone properly afterward, for the same reasons. Travel information can be found in books. What can't is the social element.
Expeditions are usually very intense experiences.
Friendships are made or destroyed, and the less organized an expedition is, the more the tendency is toward the destructive end of things. People always look for someone to blame, and the expedition leader can easily become the target of such venom. Some of the most successful expeditions anticipate this and have both a leader and an administrator. The leader is usually the motivator, the one who carries the vision. Few of these people are interested in trivia like administration and cannot understand why the rest of the team doesn't always share their vision, even on those windless evenings when the mosquitoes and doctor flies are at their most aggressive, the insect repellent has run out, and the boat is stuck on a sandbar till the next high tide.