Interactive science simulations (sims) have become popular tools for science educators, and research confirms that sims can improve student learning (Rutten, van Joolingen, and van der Veen 2012). Over the past 15 years, the PhET Interactive Simulations project at the University of Colorado Boulder has created a collection of 150 open (free) educational sims for teaching science and math. Teachers bring these resources into their classrooms, now with over 100 million uses per year. PhET sims are highly flexible tools that can be used in many ways in the classroom. Teachers new to sims may wonder how to get started. In this article, the authors turn to experienced teachers for guidance. They share responses from over 1,500 PhET-using high school teachers on how and why they use PhET sims (Perkins, Moore, and Chasteen 2015), and they present ready-to-use lessons contributed to PhET's activity database. These lessons exemplify a variety of common, effective sim-based instructional practices.