Decoherence caused by environmental noise is a major obstacle to developing a quantum computer.  We have developed a scheme, which is based on the phenomenon of coherent population trapping (CPT), to sense the spin bath noise surrounding a NV center in diamond and to stabilize the NV center with feedback control.  In this talk, I will present a theoretical analysis of the scheme and will also discuss preliminary experimental studies, including a proof-of-principle experiment on the CPT-based sensing and a feedback control experiment on the photon number distribution of optical emissions from a NV center.