Or you could go the other way and have them earn what you give them, that way they are in control of what they GAIN rather than what they LOSE, its better for them to see they are getting something out of being decent than losing everything to being naughty or disobedient
as for rules, weigh up what your kid is capable of taking on, the last thing you want is to set them up to fail, KISS and all will be well, you can move the goalposts slowly as progress is made and your child will start to feel good about themself