The below links are not for beginners - this is no 'how to write' for erotica authors (or any other would-be-writers), but rather information, opinions, and thoughts by others who write. Not all are 'for erotica authors' - but then, those who think erotica isn't about good writing, well, it freaking shows people.
So, read, learn, & see what you can (and should) apply to your writing:
The appeal of "real women"
The Big Love Scene
Talking points in the teaching of composition
Emotion, Evolution, and Rationality
Extra points for those that have the guts to post comments on what they think of the above articles.