How do I manage big cross-functional product launches?

You can run most launches now, but the big cross-functional ones still trip you. That is because scale changes the game. A small launch you can hold in your head. A big one has more teams, more dependencies, and more ways for a quiet gap to become a loud problem. Getting tripped there is about complexity, not competence. The thing that trips you is usually the space between teams, where each assumes the other has it handled and no one does. The work is not harder inside each team. It is the seams that fail. Big launches are won or lost in the handoffs, and those are easy to miss when you are watching the parts. For the next big one, list every place where one team hands to another and put a name and a date on each. Watch those seams like a hawk and let the teams run their own parts. The overwhelm shrinks when you stop trying to manage everything and start guarding the joints where things actually break.