I have already been through it twice with boys and just starting again with dd. OH, the joys of being the parent of a teenager!
I keep hearing this little saying, "Grandchildren are our reward for not killing our teen agers." LOL so my little dgd is my reward for allowing her father to reach adulthood! Besides now I get to tell him "you just wait, pay back is hell!" LOL
Stand your ground. and, please, please, please, pick your battles. When everything is a fight, make sure the issue is one you are willing to fight to the finish for. If not, you will end up giving in and that just makes it worse the next time.
Also, when the attitudes start running rampant take a look at how much sleep they are getting and what they are eating. Either of those will cause an issue.
Dd was getting a bit mouthy yesterday and even had issues with a friend at school. She decided to go to bed between 8 and 8:30 and was sound asleep in minutes. She has been going to bed on time but has show choir practice every afternoon and is getting up an hour and a half earlier than she used to so that she has time to get ready (hair, make up and plenty of time to make sure that uniform didn't suddenly change from yesterday or whatever it is she is looking at in the mirror!

) This morning she was up, raring to go and my nice little girl was back again

Plus, she made plans to hunt up her friend this morning and apologize.