Give thenthem choices!
We follow the "Love and Logic" parenting technique (www.loveandlogic.com, and LOVE it) which speaks about giving kids a much control as possible so that parents can take control when needed…i.e. I have given you many choices and now it is my turn to make a choice.
Along these lines, one of the things that has worked well with our three year-old is to give her choices of how they want their room…like "would you like your light on or off when I leave?", "would you like me to leave the door open or closed?". Even silly things like asking which pillows she wants in her crib have become part of our ritual.
Ultimately keep to a routine.