Give it time. Changes to behaviour can take up to three weeks to become habit. Don’t expect results overnight.
Choose your battles. Figure out what is most important to you in terms of behaviour, and start on that. If you try to tackle everything at once, you’ll only overwhelm yourself and your child.
Consider timing. If you’re trying to get your child or children to adopt new manners and rules a day before you head to your in laws, you’re fighting a losing battle.
Plan your strategy, and start early, if you want success.
Don’t expect smooth sailing. No child suddenly wants new rules, but they are important for family harmony. Expect a little rebellion, and you’ll be better equipped to handle it calmly.
Involve everyone. If you’re the only person applying rules, but your partner, babysitter, or your child’s teacher is not, you’re never going to make any headway. Get everyone involved clear on what the rules are, and make sure they are enforcing them.