As our primary goal within this project, we will study efficient readout schemes of the electron spin of single NV centers in diamond, aiming at projection noise limited spin readout in nanoscale magnetic resonance applications. The NV center in diamond is routinely employed as an atomic-size magnetic field sensor to read out NMR and EPR signals of nanoscale spin ensembles such as single biomolecules. Its electron spin is traditionally read out by non-resonant fluorescence, an approach which is technically easy to implement, but highly inefficient, requiring as much as 1000 experimental repetitions for a single spin readout. To improve on this issue, we will implement and study different readout techniques, such as readout assisted by local nuclear spin quantum memories or advanced multi-color laser pulse schemes. Although we will focus on the application of these schemes in nanoscale magnetic resonance applications, we expect our results to be of relevance for several adjacent fields, such as quantum information processing or electric readout of electron spins in other materials than diamond (EDMR).