We use natural consiquences whenever possible. If they break something they have to pay to replace it. When they start driving then a natural consiquence for tickets or any other infractions would be loosing driving privilages for a certian amount of time. But I'm hoping we won't need that one.
We would ground them for sneaking out, going somewhere inapropriate or missing curfew without a phone call and a very good reason for being late (I'm talking missing it by 30 minutes or more) because grounding seems like a logical consiquence for those things. But thankfully we haven't had to do that yet.
Something esle we do is that if they've done something that has negatively affected someone else then we expect them to write a sincere appology. It's something we started with them in preschool and it may seem a little over the top but it's really effective. It forces them to think about how their actions affect others. We've only had to insist on this a handfull of times with all the girls. And at this point Meg and Abbey will write appologies without being prompted if they feel it's necessary. (which is rare)
Honestly, we don't have much need to "discipline" or punish the girls. We've been really lucky so far.