This will sound like a cop-out but I'm a firm believer that you have to treat each kid as uniquely different. For some kids, maybe even most kids, sticker charts might not work, or might even be harmful. But then there's that one kid, for which it is the perfect solution.
Experiment, but don't push too hard, esp. with strong willed children. If they find it "fun" that is a good sign, if it seems tedious or if they get upset or confused by it, move on to some other idea. Ultimately parenting is more art than science...
We had to hospitalize my son for a week due to breathing problems when he was 4. He dreaded the needles and other painful procedures and put up an awful commotion. After a particularly bad episode the nurse suggested a sticker chart to reward him for each time they had to do something scary. My wife and I were skeptical but went along, and it worked remarkably well. He eventually even looked forward to procedures and took pride in getting his chart filled in.
We've gone on to adopt similar systems when we've hit motivational roadblocks on other behavioral or scholastic challenges. Make a reasonable deal with him, and he'll keep up his end of the bargain if you do.
But this works for him. Maybe he's a future capitalist, I don't know. He's quite competitive and loves measuring his progress at stuff. The same techniques don't work with his sister, or at least, not for the same reason. For her, she enjoys doing the task more than getting the rewards, it's the experience of doing that drives her. She loves games, and isn't quite as hung up on winning. She participates in the token systems to have the sense of inclusion, but it's fairly useless as a motivator, for her.
I can easily imagine that a different child, or a different combination of child and sibling or child and parent, would produce quite different results.
Also, there's a few different ways to do sticker or token systems, and again one approach might work better for one kid than another. Experiment and observe - keep your first "prototype" simple or even treat it as a game, and see how your child takes to it. Build and adapt.