I dont use a naughty step as such, but if Charlie is naughty (like the other day she hit me in the face and laughed) The I will pick her up and put her on her chair in the dining room, which is a safe place, and tell her that it was a naughty thing to do, and she is to sit there until she can be a nice girl.
I never leave her very long, ie about a minute, and she often will say sorry when i go to her.
I think its more about calming her down and removing her from the situation.