What should i do when my 4 year old daughter does not listen to me and just says no to everything?

I got a 10 year old son, 6 year old daughter, and a 4 year old daughter. My son and my older daughter listen to me and my Husband all the time. When my 4 year old throws a tantrum we put her in time out on the bottom of the stairs. it helps for maybe an hour and she just be bad again. I need some advice on how to disipline my daughter?