This document provides techniques for conducting low-cost, fast usability testing for mobile devices. It discusses common problems with mobile usability testing including issues related to the physical devices, capturing user behavior, and testing emotional engagement. The document then recommends incremental research methods using a variety of low-fidelity and higher-fidelity techniques at different stages. Specific techniques discussed include paper prototyping, emulator studies, early app builds, and diary studies. The document emphasizes the importance of involving the product team and addressing issues quickly through methods like RITE testing.