Districts now have access to a wealth of new information that can help target students with appropriate supports and bring focus and coherence to college readiness efforts. However, the abundance of data has brought its own challenges. Schools and school systems are often overwhelmed with the amount of data available. The capacity of districts to determine which data to include in their indicator systems to evaluate past efforts, monitor progress, and make strategic plans for the future lags behind the push for data use. Indicator systems that incorporate too many data elements can be cumbersome and confusing. Data elements that are only weakly or spuriously related to college success can dilute the data system's potential to improve student outcomes and divert scarce resources to approaches that are less effective. By focusing on the best indicators of college success, schools and districts can target the right students for the right kinds of support, effectively evaluate their efforts, efficiently allocate resources, and bring coherence to their push to improve college readiness. This technical guide is designed to help districts select the indicators that have the highest leverage for improving students' college outcomes. It is written with two audiences in mind. First, it assists district leadership in understanding how practical considerations intersect with the technical issues that must be considered when evaluating the extent to which a set of indicators matters in improving students' later outcomes. However, decisions about what indicators and outcomes to include in an indicator system should not be made by district leaders alone. Therefore this technical guide is also meant for district data analysts and educational researchers. It outlines the analyses that will help districts choose among the multitude of potential indicators they could incorporate into their data systems and college readiness efforts.