I've worked on marketing teams of all different shapes and sizes over my career. On the small ones, it's all about taking ownership of an entire campaign and figuring out how to maximize your limited resources.

On big teams, it's quite different. I once worked on a marketing team of ~30 people, and learned a lot about how to lead a campaign with that many contributors:

• Clear process is everything. Everyone should know what is happening and when, including due dates and checkpoints.
• Briefs are critical. Having one document that clearly outlines the campaign strategy, goals, broad timelines, key themes, etc. counteracts a game of broken telephone and ensures solid shared understanding.
• Cultivate ownership. When dealing with a large team of marketers, it's very easy to have too many cooks in the kitchen. Allowing individuals to have ownership over their specific area of expertise (such as Content, SEO, Paid ads, etc.) gives them the ability to maximize their contributions within the boundaries set by the marketing brief.
• Communicate. Communicate. Communicate. There should be plenty of scheduled and spontaneous communication between the Campaign Lead, their PM (if applicable) and the various contributors from the team. As points of intersection arise, pull the relevant team members together for side conversations, and ensure that everyone is kept up to speed on the output.
• Celebrate. Not just at the launch of the campaign, but at key milestones that the team can be proud of. This helps to cultivate the mentality that we win as a team, and we celebrate team success.
• Finally, hold retrospectives after each campaign. Look at results vs goals. Review the campaign process. Discuss things you should start/stop/continue when running campaigns. This helps you get smarter and more efficient each time you run a new campaign.

Will your large marketing team create a "too many cooks" or "many hands make light work" situation? Dig into the tips above to make sure it's the latter.