Although I complete RC's regularly (every hour with an alarm) I somehow believe that my prospective memory is not being stimulated.
My hypothesis on the irregularity of lucidity is that I need to start linking my RC's with my dreamsigns.
Yes, it would be good if you can link RCs with dream signs, upon encountering them or if not possible then by imagining them. When you do your RCs, do you truly consider you could be dreaming right now? Are you excited? You can also try stimulating your prospective memory by projecting your intent forward, feel how the RC will result in an ld, something like incubating a deja vu, incubate the dream with your RC.