We analyze and design a hybrid dielectric-loaded plasmonic waveguide (HDLW) featuring a long propagation length and strong field confinement, for efficient control and confinement of light in the subwavelength area of ${\lambda }^2/160$ . The HDLW is then used to build compact wavelength selective components of high optical performance, including ring resonators (RR) and add-drop filters (ADF). In particular, we demonstrate RRs having a small ring radius of $2\mathrm{\mu m}$ , a low transmission loss of $0.8\mathrm{dB}$ , a high extinction ratio of $21\mathrm{dB}$ , and a free spectral range of $66\mathrm{nm}$ . Moreover, an ADF with a ring radius of $2\mathrm{\mu m}$ features a $12\mathrm{dB}$ extinction ratio, a transmission loss of $0.9\mathrm{dB}$ , and a channel isolation level of $10\mathrm{dB}$ at the resonant wavelength. The compact footprint and superior performance of these plasmonic components make them promising building blocks for future nanoscale electronic-photonic integrated circuits for data communication and sensing applications.