In my experience, it is not just the physiology of the tickle, but also the psychology of it to heighten the overall response. Most of us here will tell you that tickling is as much psychological as it is physical. Creating the right atmosphere, mood, feeling of vulnerability (with or without bondage) all help to enhance ticklishness. For some people, sexual titillation leads to being more ticklish, while for others, creeping into their minds with tickle talk builds very ticklish anticipation.
Perhaps a combination of some great ideas from others on here to make your skin softer and nerves more receptive combined with a stylized atmosphere will help get you the desired affect.
Best of luck!