Cybersickness still poses a significant challenge to the widespread usage of virtual reality (VR), leading to different levels of discomfort and potentially breaking the immersive experience. Researchers have attempted to discover the possible fundamental causes of cybersickness for years. Despite the longstanding interest in the research field, inconsistent results have been drawn on the contributing factors and solutions to combating cybersickness. Moreover, little attention has been paid to individual susceptibility. A consolidated explanation remains under development, requiring more empirical studies with robust and reproducible methodologies. This thesis aims to thoroughly explore cybersickness from five main perspectives: To begin, the thesis involves a systematic review of cybersickness-related inquiries through a comprehensive examination of existing literature. The outcomes from this review then serve as a compass to steer subsequent research endeavors. Second, it investigates the posture factor influencing cybersickness and proposes a hypothesis related to conflicting virtual and real-world coordinate systems. Through this experiment, we investigate potential method to mitigate cybersickness in the supine position. Third, it introduces a protocol called Least Increasing Aversion (LIA) to assess individual susceptibility to cybersickness triggers. This protocol ranks factors by severity, utilizing subjective and objective feedback. Then, it validates objective measures like eye behaviors, heart rate, stomach activities, and brain signals to detect and measure cybersickness. Finally, the thesis establishes a standardized framework for cybersickness research in virtual reality (VR). This framework aims to ensure consistency and comparability across experiments, aiding researchers in evaluating the impact of different factors on cybersickness. The thesis provides insights into the framework's conceptual design, technical implementation, and usage instructions, concluding with thoughts on limitations and potential future directions.