WiFi sensing has emerged as a promising technology for smart services, including gesture recognition and trajectory tracking. One of the key challenges in these applications is accurately extracting velocity from WiFi signals. In this paper, we report our latest development to investigate the impact of location and orientation on velocity extraction in WiFi sensing systems. The proposed theory demonstrates that the velocity extraction significantly depends on the target's location and orientation. Thus careful consideration of the target's location and orientation is necessary for WiFi sensing system design. Specifically, two real-world applications (gesture recognition and trajectory tracking) are presented to illustrate how to eliminate the impact of location and orientation independent in velocity extraction.