Hi,
Wetting the window with a damp/I prefer a little wetter cloth first dislodges/softens & holds the dirt in the water for the dry cloth to absorb the dirt. Sometimes I use spray window cleaner then use a dry cloth tho absorb & buff.
Whatever way you go about it, it is paramount that you don't let the water dry before you get time to use your dry cloth to absorb& buff.
Kevin WINDOLENE.