*bark dividation*
Take a broad, thin piece of bark. put it into a bright fire until it catches flame then quickly set it a little distance from the fire.
When it has stopped burning, carefully stare at the symbols visible in the charred ash-laden wood.
*fire dividation*
Once the fire has died to a glowing reddish-white mass of coals, stare into its heart. If you wish, throw some Fire of Azrael incense onto the coals (equal parts cedar, juniper & sandalwood). This will flare up & burn, but will quickly die down.
With the scented smoke rising from the divination incense scry in the coals. See what shapes the charred wood seem to form, & determine their meaning through the language of symbolism.