In terms of process, I like to try and generate possibilities ad nauseam. Once the zenith is reached there is a down hill ride that will end in 99% of them being discarded. Final shapes are then stripped down to their most elementary forms. Before finalising final forms need to be tested agains all their possible uses. If they pass all the test and rules of designs I would say you have a valuable mark that can go on to be used forever. A logo that last long generates exponentially more value over the years.