How does one make a tribute item for a particular event?

You mean make a custom wearable that's a tribute item?

yes

Pretty much the same way that you'd make any normal item custom wearable, with the CI and the overlay. There's a section about it here in the custom clothing page. You need to make changes from the original, ideally have a subeta spin on it, and when you go to submit the item you would also link the reference/tribute the item you made is based on, and perhaps explain how it's a tribute.

Hope that helps answer your question?

thank you :)