 Big Team Science, BTS, is a growing trend in which multiple researchers come together to work on a single project. This paper provides a comprehensive guide for creating, managing, and participating in BTS projects. It begins by outlining key considerations when starting a BTS project, such as building the team, selecting leaders, and choosing appropriate tools and open science approaches. Next, it addresses issues related to running and completing a BTS project, such as study design, ethics approvals, data collection, management, and analysis. Finally, it covers topics that are unique to BTS, such as authorship decisions, collaborative writing, and team decision making. This article was authored by Heidi A. Baumgartner, Nicholas Alessandrone, Krista Bias Heinlein, and others.