The best place to do this is at the Haedir fast travel point in the middle of Núrnen. Keep advancing time by pressing Circle on the fast travel point. Do this until a Drake spawns (usually within 1-5 tries). Make sure you have the "Call Mount" skill and "Graug Call" upgrade equipped. Both are mounted skills. Call a Graug and chase after the Drake, then shoot it with some arrows. However, do not "break" the Drake (meaning its icon cannot turn green). Go to an open area and wait for the Drake to attack you with its flames. While the Drake breathes fire, shoot it in the head to force it to the ground. Then, attack it with the Graug to quickly kill it. You can also perform a few more headshots while it is on the ground for bonus damage. If you "break" the Drake in the air, it will try to escape. Keep its health above 50%. Drakes can also land during combat without shooting them, but this rarely happens. The only guaranteed way is to shoot it in the head while it breathes fire.