Literature
Mary Sues and you: OCxCanon relationships
Disclaimer: Since this is a free country, you are welcome to make any OCxCanon pairing you want, it's not like you're going to get arrested. Creating stories and stuff like what I advise against here is fun, certainly. But you'll find, I think, that people will take your OC and your story more seriously (and people won't make fun of you behind your back.. Or flame you to your face)
This is going to be harsh. You might be offended. I'm already not a fan of OCxCanon, and the ones I like a far and few between.
Also, I'm not claiming to be some sort of OC making guru. I'm most definitely not, but a friend asked me to do this for him so might as