In this book, we introduce hole-mask colloidal lithography and nanosphere lithography techniques for low-cost nanofabrication of large-area (about 1 cm2) plasmonic nanostructures with different complex shapes. For the first one, we use thin film PMMA-gold hole-masks, which are prepared with polystyrene colloids, combined with following tilted-angle-rotation evaporation to fabricate large-area randomly deposited plasmonic nanostructures. For the second one, we use hexagonal close-packed polystyrene nanosphere monolayers directly as evaporation masks to fabricate large-area periodic plasmonic nanostructures. We describe the fabrication process step by step, and manufacture a variety of complex plasmonic nanostructures for different sensing applications, like antenna-assisted surface-enhanced infrared absorption measurements to detect monolayer molecules; localized surface plasmon resonance liquid and gas sensing with high experimental sensitivities; as well as single-layer three-dimensional and multi-shape metasurfaces for desired optical multi-functionalities.