Here is a handy tutorial on how to sign up for an fic exchange on AO3:
Here is the link to the signup form:
Here is the tagset:
Info about the freeform tags:
Freeform Tags & Glossary!
NOTE: Because there was some confusion about this last year:
Remember, if you have multiple prompts, you can make multiple (up to five) requests! All your prompts don't have to be in one request. I am mentioning this because last year some people's prompts had more characters than they had requested, because you can only request five characters per request. But if you make more than one request, you can request more characters.
Also, if you are requesting relationships, make sure to request those characters as well! The matching will be done by characters first! If you haven't requested those characters, but want them in a relationship, you're unlikely to be matched on those.
Here is an example of how this would look:
So you can see I had five prompts, so I made five requests. I was able to request more than five characters, because I used the multiple requests. I also requested relationships, AND the characters involved in those relationships.
If you have any questions, feel free to ask in comments, or email to email@example.com