With the rapid development of wearable technologies, the demand for high-performance strain sensors with excellent electrical conductivity has significantly increased. In this study, we aimed to enhance the electrical conductivity of a poly(vinyl alcohol)/glycerol–poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/lignin/cellulose nanocrystal hydrogel sensor, which originally exhibited real-time human motion detection capabilities but showed inferior conductivity. A multi-stage green enhancement strategy was systematically investigated using various additives, including dimethyl sulfoxide (DMSO), dialdehyde cellulose nanocrystals (DACNCs), and graphene quantum dots (GQDs). First, the addition of DMSO promoted phase separation within the polymer matrix, increasing the initial conductivity from 1.73 to 5.36 S/m. Second, periodate oxidation was utilized to prepare DACNCs, and adding this functionalized nanomaterial further optimized the conductive network, elevating the conductivity to 9.75 S/m, which is 4.43 times that of the original film. Finally, the incorporation of GQDs acted as conductive nanobridges, successfully driving the overall electrical conductivity beyond the 20 S/m milestone. The resulting composite film effectively resolves the intrinsic conductivity limitations of traditional hydrogels, demonstrating immense potential for advanced wearable applications in medical healthcare, electrocardiogram monitoring, and artificial skin.