An itinerary outlines a travel plan including destinations, transportation, accommodations, and activities. It is essential for travel agents to help clients select appropriate tours and itineraries to gain their trust. There are different types of itineraries including tourist, tour manager, and tour escort itineraries which vary in level of detail. Effective itinerary planning considers factors like travel purpose and length, transportation options, including optional activities, avoiding backtracking, accommodating check-in/out times, and communicating trip requirements.