I've been told that I'm good about keeping characters as canon as possible with the odd situations they are tossed in at times. Normally with shows that I've watched a lot. I know a lot of people like how I portray the Criminal Minds people. I get annoyed with people who get so outlandishly out of character with their portrayal of them and thus refuse to write in a fandom if I don't feel comfortable in my ability to do the character justice. I have to be able to get inside their head and think like them. So I'm picky about my fandoms because of that.
Well, I haven't written any fanfictions, but I frequently role-play and I've been told at least once that the way I write them makes it seem canon. Also, I try to fill in the gaps of the actual story from the comics/games so it would fit perfectly if it were actually canon! I think it's a wonderful compliment to hear and it always makes me feel so warm and fuzzy inside!
Same here! A friend told me that even though I have about a million different muses for characters, I write them well. I felt pretty good about that.
I use role plays to get character voices down for fanfic, and vice versa. I feel like it's good practice for me doing either one.