This How-to Guide will introduce the reader to active and passive data collection techniques when using smartphones and other mobile devices. Examples of active mobile data collection on smartphones include mobile web and SMS surveys for self-reports, while passive mobile data collection includes the use of smartphone sensors (e.g., GPS, accelerometer) and log files (e.g., call and SMS logs, app usage). The guide will discuss the scientific and practical considerations of deploying these methods and describe specific examples of knowledge gained from using these two techniques. Advantages and disadvantages of the two forms of mobile data collection will be discussed as well as how the two can be integrated to create better measures of attitudes, behaviours, social interactions, and other phenomena of interest to social scientists.