Teams that build software are largely demographically homogeneous. Without diversity, homogeneous perspectives dominate how, why, and for who software is designed. To understand how teams can successfully build and sustain diversity, we interviewed 11 engineers and 9 managers from some of the most gender and racially diverse teams at a large software company. Qualitatively analyzing the interviews, we found that they share approaches to hiring, recruiting, and environmental inclusion, all of which create a positive feedback loop. Our findings produce actionable practices that every member of the team can take to increase diversity by fostering a more inclusive software engineering environment.