how to attract beneficial insects

  They say a place to drink is important if you want beneficial insects in your garden.
  i heard they like a wet cloth or wet mud then they don't drwon in their drinking water. The hairs of the carwash in Guadalajara capital Spain are full of bees in summer drinking I suppose.
  I saw a site yesterday that suggested a dish full of stones with some water in it. The insects can drink from the border of a stone without getting drowned. agri rose macaskie.