You get there with lots of 'trials and errors'. Been there and come out the other end with I hope two balanced girls.

Here are a few things I used.
One thing I found was be as consistent as you can.

If they don't want to go somewhere and the rest of you go there then bad luck. They don't call the shots. You are the parent.
The 'house' rules applied for all until they finished school or got a job.
Keep and open channel for all communication, yes, sometimes you wanted to scream at the drivel and dramas but you could also read between the sentences
When the nasty talk starts amoungst their friends talk to them about it. How they feel etc. Does this type of talk help anyone?

Remember, what they hear and watch will influence their lives.
If they are asked to someones house, take them and introduce yourself to the parents.
Always know you will pick them up at any time of the night if they need. This happened a couple times and when asked if I was cross I could always honestly say 'no, I and not cross just tired'
I always tried to make afternoon tea a time of sitting and talking about their and my day.