The key to getting children to behave is motivation.
Give them a reason to want to do things your way. Things like: "If you get yourself dressed all the way to the shoes, you get a tootsie roll."
"If you finish your homework in less than an hour, you get a tootsie roll."
"If you put away the laundry, you get to choose dinner."
The next step is follow-through for both rewards and punishment.
No giving in to crying when you know how much they really, really wanted something. If there was a prerequisite to get the reward and they didn't do it, they don't get it. Period. If you really wanted to give it to them, you should not have given them conditions to earn it.
Punishments too. If the entire extended family is here from out of town just for the parade, you can't possibly "not go to the parade unless you finish your homework." Don't claim that will be the punishment. Choose something enforceable.
kids behave. Most of the time. I have great kids. But they didn't
figure it out on their own. I had to teach them because I am the
parent. And teaching is done inside a set of restrictions called
rules. If the rules are broken and not repaired with consequences,
their behavior will be broken too.
It stinks to enforce rules. But it stinks more to be unappreciated, taken for granted, lied to and disrespected.
We try to avoid the rules completely by motivation. We aren't even on the punishment end of the spectrum....most of the time.