Give your child lots of descriptive praise when they do something that you would like to see more of, e.g., "Thank you for doing what I asked straight away".
Teach your child new skills by first showing the skill yourself, then giving your child opportunities to learn the new skill. For example, speak politely to each other in the home. Then, prompt your child to speak politely (e.g., say "please" or "thank you"), and praise your child for their efforts.
Set clear limits on you child's behavior. Sit down and have a family discussion on the rules in the home. Let your child know what the consequences will be if they break the rules.
Have realistic expectations. All children misbehave at times and it is inevitable that you will have some discipline hassles. Trying to be the perfect parent can set you up for frustration and disappointment.