Today's tip is from Heidi:
"Give your child lots of choices."
So rather then saying "It's time to leave", you'd say, "Would you like to leave now or in 5 minutes?" Or when disciplining you'd say, "Would you like to go to time out or your room?".
Heidi got this idea from a book called Parenting with Love and Logic. I've heard really fantastic things about this book.