Through the years, I have seen a lot of couples who had problems raising their kids. It may be common when the issue centers on making more money for the family, and now another one raises a lot of concerns for growing families. That is, getting your kids to behave well.
That is why it is important to serve as a good model for your kids. Gone are the days when we were less careful of our ways. We have to watch our words and actions. We need to be the person we want our kids to be. Most of the kids nowadays do not appreciate it when we scold them or nag them on how to behave in certain situations. We have to show how to do it through example.
If that does not work, then it is best to talk this over with your kids. Please do not resort to reward system as this get abused by kids most of the time. They get to act good because there's a reward waiting for them, until the reward isn't that much desirable to them that they revert to their bad habits.
Tell them why they need to improve on a specific behavior in words they can understand. Highlight the importance of practicing acceptable behavior in and out of the house. Then give them time to process and do it. When all else fails, then it is best to consult experts in child psychology to help you out in getting your kids to behave well.