Professional organizations serve as a great resource for all writers. Many provide a wealth of resources and networking opportunities for both aspiring and established authors writing in just about any genre.
The following list is by no means comprehensive, so I encourage you to seek out organizations that meet your specific needs as a writer.
Horror Writers Association (HWA)
National Association for Independent Writers and Editors (NAIWE)
Romance Writers of America (RWA)
Science Fiction & Fantasy Writers of America (SFWA)
Society of Children’s Book Writers and Illustrators (SCBWI)
Aristeia 