There are different ways to segment users - marketers and user researchers typically use the interview or survey methods and segment users based on attitudes or intentions. By contrasts, data analysts can use behavioral data to generate segments in a semi-automatic fashion and with little assumption about a user's needs or intentions. This approach is particularly useful for understanding product usage, tracking user growth, and informing product decisions. But blindly applying clustering methods can produce woefully bad results. We will walk through a real-world segmentation exercise run at VSCO to illustrate how to properly apply clustering methods and avoid analysis pitfalls.