It's MUCH easier to work with a hatchling or young juvenile tokay, and many people have had success taming little ones before they get to a more stubborn age.
There's no real trick to taming a tokay...you just need to be patient, gentle, and persistant...and have really thick skin. <G>
Some folks recommend starting handling with gloves first, or putting the animal into a cloth bag, and holding the cloth bag first. Others say just grit your teeth, and pick up the gecko...don't restrain it too roughly. Short sessions every day will eventually get you to your goal.
I believe there's one tokay breeder out there who's specifically selling tamed tokay juveniles.

At least, there was a couple of years ago.