Hello,
I have been reading stories posted to this site for about a year. I must admit, I found the range of subjects fascinating, and the range of quality astounding.
Some of the authors who post here are excellent writers with vivid imaginations and superior skills. Others are not quite as good, but who, with a little patience and a great deal of editing, could become much better.
There is good information and advice about writing already available on this site, and I would like, hopefully, to add to that body of work.
Before I go any further let me refer you to the 'Writer's Resources' section of the site and recommend that you familiarize yourself with this valuable resource.
If you are truly desirous of improving your skills, I seriously recommend a good book on basic grammar. Your bookseller can direct you. Buy one, read it cover to cover, and refer to it often. The advice regarding English grammar available on this site is conflicting, and sometimes incorrect. Therefore, you would be well served to research this subject independently.
You can use incorrect grammar in your dialogue because your characters may be poor grammarians, with good plot related reasons. Your narrative sections, however, are written as your voice. Poor grammar shouts 'poor writer.' Good writing demands good grammar.
********
What follows now are my personal thoughts about writing erotica and how I approach the subject when I write a story.
Writing erotica is a little different than writing for other genres. An erotic story focuses on intimate, personal interactions between people. I believe that what makes a story erotic is not the descriptions of characters having sex, but the reader's ability to relate to the characters, as if s/he were part of the story and therefore part of the action.
For me, the best way to accomplish this is to develop realistic, interesting characters. I try to do this through description and dialogue, mostly dialogue. I also go to great lengths to make my writing readable. By readable I mean a natural flow with short paragraphs and easily identified dialogue from my characters.
Realistic characters are easy to create. They are all around you. They may even be you. The trick is to give enough information about your characters so your readers can form a mental picture of the person you are writing about without overloading your story with excessive details.
A brief description is better than a detailed one. Your readers will automatically fill in the details from their own experiences. Just give them the basics and they will create a mental picture of the person they want to 'see.'
For example, here is the description I wrote for the title character of the 'Amanda' series:
"She was wearing a white T-shirt, baby blue shorts, and white sneakers with those short quarter socks. Hers had a blue trim that matched her shorts. From behind, she looked very athletic. Her long blond hair was tied in a ponytail that hung to the middle of her back. She had a slender waist, narrow, almost boyish hips, and a world class tush. Her legs were long and well muscled."