We review some of the recent advances in the simulation of plasmonic devices, drawing examples from our own work in metal-insulator-metal (MIM) plasmonic waveguide components and networks. We introduce the mode-matching technique for modeling of MIM waveguide devices. We derive the complete set of orthogonal modes that the MIM waveguide supports and use it to apply the mode-matching technique to the analysis of plasmonic waveguide networks. We also introduce several different equivalent models for plasmonic waveguide components, such as the characteristic impedance model for deep subwavelength MIM waveguides, the scattering matrix description of MIM waveguide junctions, and equivalent circuit models. The model abstraction provided by these equivalent models is important for the analysis and synthesis of device functions, as illustrated with the design of a waveguide mode converter.