This is something I adore doing. There are so many possibilities when creating an original Clan, though there still are rules you should follow. I strongly dislike when people shun original ideas though, like islands or treetop Clans or jungles. Those could all be very interesting and creative and can all work if you plan it out well.

Another thing I dislike are clone Clans. Like if there's a fanfic with StreamClan, GrassClan, StormClan and NightClan and they're literally just the original four Clans with different names. It's alright if you don't want a new setting, but you know you can just use the original Clans then, right? There's nothing wrong with that.

I personally have a StreamClan, but they aren't a RiverClan clone. They don't even really fish, their territory is just filled with small streams that are too little for any substantial fish to be there. They mostly eat squirrels as they live in a lush and plentiful part of the forest, they can climb trees and said trees are densely placed. Because of the streams, they also catch a lot of frogs. See? Originality is possible.

Think of new settings, places that cats could live. I also have a TreeClan where their trees are so densely placed that they can live on top. They hunt birds and squirrels and fight using the trees to their advantage for surprise attacks, and no other Clan knows where their camp is. I know it isn't the most realistic, but hey, it's something new and I made it work.

Just remember: only name Clans after things the cats know, and it should be simple. It can either be named after the environment or the founder, or both. All Clans are named after the founder and I think that's most obvious with ThunderClan in canon, obviously they aren't living in thunderclouds, but their founder was Thunderstar.

The cats should also match their environment. Like RiverClan cats have sleek, almost waterproof pelts for swimming, ShadowClan cats are normally dark furred to blend in with the shadows, WindClan cats are built for speed with short fur and lighter bodies, and ThunderClan cats are often light on their paws to avoid making noise as they move through the forest.

So there, I think that's all I have to say, but I'd love to hear about everyone's Clans! I love FanClans-