The double blind experiment. Build and test two identical gadget: the first loaded with deuterium dioxide (heavvy water), the second with hydrogen dioxide (water). The first works as Cool Fusion test cell, the second it is used as reference in order to certify the excess enegy production of the first one
Optimize the Cool Fusion cell for direct energy conversion. Starting with a semi-classic cold fusion cell, the initial direct conversion efficency is very low (less than 1%): most of the excess energy is released as heath. Basically, there are three way to convert the excess energy to electricity, but we still don't know wich is the best.
Integrate the Cool Fusion cell with a conventional lithium rechargable battery.