here are some CDP tweaks that are very worthwhile...
Upgrade AC cord:
(& not all cords sound alike - I'm using a "relatively inexpensive" JPS Digital AC at the moment, but have tried many others - system synergy & your sonic preferences deterimine the best choice).
Coupling, Isolation & Shelving:
I have my CDP up on Nordost Pulsar Points (in titanium option - didn't try the cheaper aluminum's) but I have also tried many others such as carbon fiber Black Diamond #3's & #4's, brass Audio Points & pucks, ceramic DH Labs, & titanium Orchard Bay cones with brass pucks. Every cone has a different sonic signature & again, system synergy & your sonic preferences deterimine the best choice. Varying the spacing between cones changes tonality - further apart = brighter / more detailed, & closer together = warmer / less detailed.
Presently the cones/pucks sit atop a Zoethecus Z-Slab shelf, which is my dead-mass for absorbing the microvibrations coupled into it via the cones. Black Diamond shelves also work very well but have a slightly different sonic signature. Again, system synergy & your sonic preferences deterimine the best choice of shelf.
In order to isolate the dead-mass shelf from the rack's vibrations, I have the self siting atop a set of Vibrapods (model #'s chosen for the total weight of the "stack").
Interconnects: some people tune their rigs by changing interconnects - even the choice of digital cable has been reported to have profound effects, in addition to the analog cables. I chose my cables for neutrality & do my tuning as-above, but others chose to do it via their cabling as well.