I find sometimes that the mental element is a factor rather than the pure tickle method or place on the body.
I often blindfold the lee so they don't know where the tickle attact is going to come from if i'am silent enough.
Using baby talk can make them laugh or anger them, i never use gags because i like to her the laughter, squeals, screams, begging, pleas, and comments like calling me a bitch so i have the excuse to punish further.
I explain in great detail exactly what i'am going to do, like remove a watch and say "the only thing you will be waring will be your after shave" " i will drown you in your own sweat" then sometimes do something different.
Slowly tease and take time stripping them teasing as you go.
Try going near to the ticklish areas but not quite making it, then when your tickling a less ticklish area just run a feather or finger nail along the groin and on the penis, if errect feather up the back and run a finger nail along the front just a light tease, then move away but keep doing it.
Two years ago my mentor taught me about hot and cold, sharp ice cubes when your blindfolded can feel like a knife, the one foot iced and the other warmed with a hair drier adds to the sensation of tickling, sometimes it compliments it some time not, different moulds for the ice cubes is a idea, a thin slice for going between butt chheks, or a round tapered iceicle, saying no more on that.
The salon wher i have my hair styled save human hair from the long to short styles, and makes up brushes, the one girl who does the massage is into tickling, so improvise look at what can be used to tickle and save it for a suprise, even a metal dog comb is a instrument of tickle tourture on the feet with oil.
The more tickling you do the more you learn so good luck.