First- this gotta be moved to story ideas, I guess?
OK, what I'll talk about is what I like in a story, because some parts are different when it comes to real life.
First of all - in any story, really - I like the girl's experience. Even if the story is non-con, I like when in the end she gets to be happy. In sex she gets her needs fulfilled, be it lots of orgasms or in case of denial - let her enjoy the humiliation and frustration.
I like long thought-out sex scenes, with the descriptions of every caress, emotion, scent; the thoughts that go through the minds of the characters, ets.
Also in general I dislike when the looks of the girl are described too much. I find it distracting when the image portrayed does not suit my tastes. That's especially annoying when it's done after awhile, when I already ahd a mental picture in my head.
I prefer to describe the general body type and hair color, and leave the rest to the readers' imagination.
BDSM-wise I like creative ways of bondage, as well as predicament bondage. I enjoy long predicaments where a girl is being tied up for hours, although I can't do that in reality.
I enjoy forced orgasms fetish a lot, where she's made to cum until it's painful and she's begging to stop. I enjoy edge play, where she's brought to the brink over and over and left frustrated.
I enjoy the concept of sensory deprivation too.
I enjoy control and submission themes a lot, when a girl is willingly giving herself up as a sex toy of sorts, trusting her master to do what's good for her even if it makes her cry or be in pain.
At the same time I hate when the master is inconsiderate to his sub or plays dangerously. I like to see that even when he's a complete sadist, getting on her pain, humiliation and tears, making her scream and beg and plead - he still takes every precaution to make it save, to care not to leave scars and stuff. That's a bit of a mindfuck too, when you know he's preparing to hurt her, maybe even past her limits, but at the same time you see he's preparing to make it safe, caring for her eventual well-being.
Fetish-wise I like pet play and lactation/breastfeeding fetishes.
have fun! Remember, you can write pretty much about anything you like, and there'll be an audience for that.