To hang Christmas lights on brick, you'll need to use specialized clips designed for brick walls. The clips will attach to the mortar joints, which are the spaces between the bricks. You can also use screw-in hooks if you're hanging heavier lights or decorations. Make sure to read the instructions for the clips or hooks to make sure they are compatible with your type of brick. And remember, safety first! Always wear gloves when handling sharp objects and make sure to use a ladder to reach the higher areas.