L.S.
In our house, we have one "rule" per year for our children. So, my 2 year old has 2 rules; 4 year old has 4.
The first two for both of them are:
1. Listen to mama and daddy (pretty much covers everything! lol)
2. Treat people the way you want to be treated
Then the additional ones are
3. We take care of our house and belongings
4. We follow the rules outside of the house too (ie at school).
With my daughters, I find that if they're misbehaving I just ask them to repeat the rule they're breaking back to me. Then I ask if they're following that rule. When they say 'no', I say 'well, let's try again'. And they're usually pretty quick to correct their behaviour. Of course, I realize this may not work with every child, but it's a place to start.
We also have sub-rules (like no running in the house, no eating in the livingroom), but those fall under the 'listen to mama and daddy rule' :o)
As for discipline, we use time-outs modeled after the Supernanny method. I've also learned that maintaining MY cool helps to keep the situation from getting too intense. My oldest daughter is JUST like me (demanding, stubborn, sassy know-it-all), so we butt heads a LOT, but I'm definitely getting better at remembering that it takes 2 to argue and I'M the adult!! Hahahaha, hopefully by the time she's 12 I'll be a totally zen mama ;o)