There are a multitude of dry shampoos on the market. My very favorite are any of the dry shampoos made my Batiste. Suave also has a new dry shampoo out that works well and is a few dollars cheaper. The standard directions are to hold it about six inches from the roots, spray and work it into the roots. Then just brush it through.
I’m not going to say that my hair looks exactly the same as when I just washed it as that just isn’t the case with my hair. But, it soaks up the oil and lets me pull it up into a ponytail and gives is a just-shampooed smell. Some women even use it on the day that they shampoo or before going out. Spraying some on the roots adds volume to hair that has gone flat by the end of the day.
I personally cannot go any longer than that without shampooing and probably wouldn’t want to anyway. For women with dry hair, perhaps use it for an extra day or two if you can get away with it. I credit dry shampoo with saving my hair color, as well as a lot of time that I would spend washing and blow drying my hair.