Abstract We present several developments aimed at improving the stability of optical lattice clocks. First, we present our developments of an optical lattice clock using neutral mercury. We mention recent advances made with the fermionic isotope 199 Hg. We also mention our work aimed at using bosonic isotopes, which offer the possibility to circumvent the relatively short lifetime of the upper clock state in 199 Hg. Second, we present our work on a non-destructive detection in a Sr optical lattice clock. We describe developments that brought the detection scheme from the classical non-destructive regime to the quantum non-destructive regime. Our detection scheme is practical and has the capability to the used beyond proving the principle. Finally, we present our work on laser stabilization using spectral hole burning in a Eu 3+ :Y 2 SiO 5 crystal at cryogenic temperatures. We describe our development of low noise interrogation based on digital IQ modulation and detection that can probe multiple spectral features simultaneously, as well as several investigations towards fluctuating environmental factors. These advances, individually or combined for example with spectral purity transfer with combs and composite clock approaches, shall bring significant progress in clock stability and accuracy.