This might have a less procedural answer than a lot of the questions here, but how would one bridge the gap between agent-mediated travel, with a schedule drawn up for you ahead of time by someone that presumably knows what they're doing, and just hopping on a plane and hoping for the best?

This is more of an issue for long trips to unfamiliar places; selecting a hotel for a few days' stay isn't hard, and renting a car isn't much harder, but creating an itinerary beyond that is a skill I haven't acquired. Particularly if I'm going somewhere where the local language isn't one I speak well.