Power - where to start? Mains, chords, conditioner, filter?

I have a decent HiFi setup with all power cables as delivered by the manufacturer of the unit. I am contemplating upgrading the power infrastructure, but is a confused where to start? What makes the biggest bang for the buck? Power chords to each unit, mains blocks, mains conditioner, mains filter? Any advice before I move into this world? 

I have a streamer from Innuos being used for Tidal and Internet radio. A DAC from RME and an integration amplifier from Musical Fidelity. 

I live in a flat in a capital and the electricity is probably good, but for sure the SQ is better late evenings, which to some extent is leading me down this route.