what to do with a sassy girl

Looking for suggestions...

Alex has become quite a sassy girl. Lately the attitude, arguments, and backtalk have just escalated. It's time to put the lid on it.

We've tried a few things. We usually give her some time alone until she is ready to rejoin the family. Mostly I think we just need to be more consistent. I also want to teach her constructive ways to express her anger, disappointment, etc. instead of just silencing her. I'm wondering what other experienced parents have done that worked. Anyone care to share?