Mild soap or detergent such as a boat wash. Gently Wipe with SOFT, CLEAN cloth or Microfibre cloth. Once dry apply a good quality paste wax and in the future it won't be difficult to clean.
DO NOT use Windex with ammonia or any other so called glass cleaners or you may ruin the material. No abrasive pads either.
There are polishes that will help if the surface is really hazy such as Novus or FLitz.
However, a good paste wax will take care of a lot of that.