Traditions are fun in anything, especially in fantasy. Think about traditions you've started yourself. Think about other traditions from other parts of the world.
They don't have to be connected to a holiday or anything special, they can be simple, mundane things. For example, when we moved to Alaska, the first time we invited anyone over, they asked if they should take of their shoes. I raised an eyebrow and said, "We're not in China or Japan". I had never heard of anyone doing this. But the reasoning is simple in this example, it's wet and muddy outside and people don't want stuff tracked all over their nice homes.
Look at the tradition of bowing in the Asian countries. How over in the middle east, the left hand is used for hygiene and considered unclean so you must eat with your right hand. Marriage proposals and engagements vary. Funerals are all dealt with differently. Even the birth of children are widely diverse. Living in Alaska, there are a lot of orthodox Russians and I see a young couple holding hands constantly and it is part of a tradition, I think, the day before their wedding. It's kind of fun to look up a lot of these traditions and figure out where they started and what they will be.
Traditions in fantasy world building are just as important as they are in our world. They pull people in. Family, friends and in certain situations, total strangers. It creates a bond where you feel connected to other people even if it is only for a fraction of a second.