i don't know if there is a way of taming him, after a while of your interacting they will realize you're taking good care of them and be more open to being lightly handled
as far as training goes though
its almost "dog whispering" tactics
i you want to train your cham to be a good hunter, don't flood his cage with crix cuz he'll think he can just sit and one spot and nab one when it comes by, which is fine, except for when he needs to hunt because there is only a cricket or two in his cage.
also i think that if you are quick to provide tons and tons of drinking water, your chams will be accustomed to not having to scrape every drop of water off the leaves, which is why we like it to dry out for a half an hour or so before they get water again, and only turn it on for a few seconds at first
so they seek out the small amount of water, then after awhile you can let them have timed 20 minute mistings and such, just don't want to spoil them or they'll never drink when you only have a minute to mist them!