What is the most effective way to discipline my five year old? I feel as if I am completely losing control of my five year old daughter. She has always been pretty rambunctious, but lately it is getting to be a very big problem. I have always used time-

Clear, firm, calm. Most parents get into trouble because they become upset with the child and frantic. You should be trying to teach her how to control herself. You know what is good behavior and you are going to teach her how to behave well. Offer her approval when see does not and calm punishments like "times out" when you need to interrupt a behavior. Firmness, not anger. No spanking or anything like that.
A. A difficult problem. It sounds like you have been doing fairly well with using time out and scolding as necessary to discipline her. Something changed when she went to kindergarten. I suggest that you get professional counseling /help with her. It sounds like something might be bothering her. It may take counseling to find out what's going on and to help you with dealing with this. Best wishes.