Having sold one story, I was afire to sell more. Also, since at that point I already knew writers and editors, I wanted to sell more stories as efficiently as possible. So I researched, using several methods.
1. Asked people. First Cecilia Tan, as I said, and also various editors I knew through a friend who used to work at Tor Books.
2. Read calls for submissions. The one I use now is erotica-readers.com, but it took a while to find it and decide that was my favorite over some other sources. Reading calls for submissions is more educational than it sounds. You get a picture of how the market might be shaped in the future as well as familiarity with ongoing series of anthologies and prolific editors, plus the more basic knowledge of what kind of story is in demand and what kind isn't.
3. Read current anthologies. I can no longer remember how many anthologies I read, some in their entirety and some skimmed. I learned this way what had actually sold, and tried to figure out why, and compared what one editor had bought to what another editor might have chosen. I didn't come to systematic conclusions in a formal list, but I formed valuable impressions. Then I got tired of reading erotica. Today, when I receive a contributor copy, I rarely read the whole thing. Sometimes, I read none of it, though I usually glance at my own story to make sure no glaring typos snuck in.
4. Made [more] contacts. Finally, I learned about the market by submitting, and editors could learn about me the same way, or at least become familiar with my pseudonym. Whenever there was a reading for an anthology I was in, and it was affordable to get there, I went, and met other writers and editors. I met sacchig this way, at a Best Lesbian Erotica reading in New York. Years later, contacts like this began to pay off as editors to whom I'd sold something, or whom I'd met at a reading for an anthology, sent me private calls for submissions, or asked for reprints of my stories. Not that I knew at the time that this would happen. I just wanted to meet other writers.
So, while acquiring all this knowledge, I worked on more stories and tried to apply what I'd learned. Stay tuned to this LJ for the next exciting installment of The Tale of an Erotica Writer!