Considering most writers are human (or so they'd lead us to believe)
I'm not....
Since my main character is a dragon albeit one forced to be in human form the majority of the time I find it great fun trying to figure out how a dragon would handle situations that are an everyday aspect of being human, what their perspective would be on traits mankind has that their own species do not, and other such issues along those lines. So I was curious how others handle writing nonhuman characters that are not villains/monster of the week type characters.
I usually use it for worldbuilding jokes, many of which quite rightly never make it to the final MS. My dragons are vegetarians, for instance. You can use mythology, etc.
how do you personally incorporate a nonhuman perspective? Do you use them as a means to make commentary on mankind? Foist human issues onto a supernatural being and see how they handle them differently? ... Are you ever concerned that as a result you get preachy?
Depends. Despite all the advice against writing anthro characters, the only compelling argument I've heard against it is the furry porn thing. I don't like reducing any character to a particular perspective. I think if one is going to use animals or non-humans there should be something gained by it, but my standards are quite low in this regard. Many of my favourite books have non-human characters, sometimes more and sometimes less human-like. It's funny how often I meet other readers who love these books, too.
Any fictional universe we write is going to say something, by natural extension it will often involve mankind, especially in science fiction. The temptation might be to make this some big commentary but any character relates to any theme in a certain way, even obliviously (whether or the character's part or the writer's depends). A non-human character introduces an element of difference, but difference does not have to be important.
It should be explained, though, at least within the world's broader suspension of disbelief.
Do you ever worry that readers won't relate to nonhumans?
Always. I'm not an anthro writer, I just have a WIP that went that way kind of instinctually and the whole thing just works better since that occurred, so I go with it. One of those gut things I can't really explain. My favourite character is a rabbit. It's not because she's a rabbit but because of who she is and what she does, but similarly she would not have been able to do those things without being a rabbit. This is my defense against the worrying over relatability. I have no idea if it's adequate but it's what I've got.
Though now I come to think of it, an impromptu list of my favourite characters in any story (including other media here) would probably include an undead, a squirrel, an elf, a quarian, a lion, and an Ix from Betelgeuse 7.
I find the whole concept interesting so please, discuss away.
Glad to chime in.