Future technologies underpinning high-performance optical communications, ultrafast computations and compact biosensing will rely on densely packed reconfigurable optical circuitry based on nanophotonics. For many years, plasmonics was considered as the only available platform for nanoscale optics, but the recently emerged novel field of Mie resonant metaphotonics provides more practical alternatives for nanoscale optics by employing resonances in high-index dielectric nanoparticles and structures. In this mini-review we highlight some recent trends in the physics of dielectric Mie-resonant nanostructures with high quality factor (Q factor) for efficient spatial and temporal control of light by employing multipolar resonances and the bound states in the continuum. We discuss a few applications of these concepts to nonlinear optics, nanolasers, subwavelength waveguiding, and sensing.