I'm currently setting up a harvest festival area for fall. It's got games and stalls with pinwheels and bubble blowers and I've got haybeds and mush items and soon it'll have Halloween items... it's going to be awesome! I even moved Pietro in so I could have a clown
And, of course, I cleared out a good amount of space today where my pumpkin patches will go 
Then, come winter, I'll probably take it down and replace it with a festive winter festival area ☺ I'm actually really excited to think of how I'll change things around for different seasons, and just change things around in general. Everyone seems to be talking about "finishing" their islands, but that's not what I'm trying to do at all. I want to keep changing my island around- it makes it more fun for me!
Then, come winter, I'll probably take it down and replace it with a festive winter festival area ☺ I'm actually really excited to think of how I'll change things around for different seasons, and just change things around in general. Everyone seems to be talking about "finishing" their islands, but that's not what I'm trying to do at all. I want to keep changing my island around- it makes it more fun for me!