I) If I can see a church, I observe the way it is built. All churches are normally built with the altar at the Eastern end, so that when all the believers turn to the altar to recite the Credo, everyone is facing East, towards Jerusalem. So if you stand with the altar on your right hand side, you will be facing North. In larger churches and cathedrals there is often a north transept, so you can follow the line of it.
II) If someone in your party has a timepiece, wait until the hour of noon. A sundial is frequently to be found on the wall of a house or a church. When the sun comes around to noon, it will be due south. Stand with your back to the sun and you will be facing north.
III) If there are no churches or houses to be found, look around for a copse of trees. Examine the bark of the trees. Moss and lichen will be growing on the north side, away from the hot sun and dryness of the South.