How to find the Griffin in Dragon's Dogma.

The Griffin is first encountered by the player in a real-time event in which a caravan is being attacked by Goblins outside of Gran Soren; the Griffin swoops down, and catches the player off guard.

After that, the Griffin remains highly elusive to the player. Encounters are minimal, and even then it is not guaranteed that the player will fell the beast. Thus, it is highly likely that the Griffin will ignore you, and leave the area.

This monster can be fought in the main storyline quest. However, it is not recommended that you rush the questline; so that you may fight this monster alone. Instead; we will find a Griffin on the world map.

The Griffin is often spotted in the following areas:

Eradication Site
Estan Plains
Northface Forest
Moonshower Cliffs

One way to encounter the Griffin is to leave Gran Soren, and start on the right path. You will know if the Griffin will be in the area if the you see a bandit archer atop the ruins of the former Gran Soren wall. Continue along the path, and you should see some more bandits making use of Ruins. They will rush you. Fight them, and create a spectacle; by now if the Griffin is within the area one of your pawns should announce something along these lines 'A grifffin!' Keep an eye on the skies, and pay close attention to where
the Griffin actually lands.

One area in which the Griffin will always spawn is the Eradication Site. (Look at the map for location; it's to the west of Aernst Castle) Make sure you leave for this area at dawn; as the Griffin will leave if night falls. Once you are within reach of the Eradication Site make sure to save. This is important, because you're encounter with the Griffin will probably not go as you initially planned.

A little to the south of the  Eradication Site are a few Goblins on the beach area. Go there, and start to fight them. Leave some of them to call in reinforcements. Run around the area, and your pawns should announce the Griffins arrival. Chances are it will not go after you, but some other creature in the area. You MUST run up to it, and try to scale it.

The creature can not leave so long as someone has a hold of it.

Another tactic I use at the Eradication site is to kill an enemy, and hold their corpse while standing perfectly still. This should trigger the Griffin to make it's initial descent.

What you do now is up to you.