When aspiring children's writer Sally Jones Rogan joined the Society of Children's Book Writers and Illustrators in 1987, she barely knew a pop-up book from a picture book.

Now, having published short stories in national children's magazines, Rogan credits the society with helping her achieve success.

"Competition in children's writing is tough," says Rogan, who lives in Woodland Hills with her husband and two children. The group "gave me tips and plenty of networking to make my first sales."

The society, founded in 1968, recently moved into permanent headquarters in West Hills. An international organization with 9,000 members and 60 chapters, the group is widely respected by children's book publishers for the guidance it provides hopeful writers, members and publishers say.

The society "is great for beginner writers as well as those who have some experience under their belts," says Sue Alexander, chairwoman of the society's board. "Children's writers and illustrators are very giving people and share information. You just can't be a pessimist in this kind of field."

Children's book writers have become as ubiquitous as Los Angeles screenwriters in recent years, according to Tarzana-based Southern California Children's Booksellers Assn.

"There's been a tremendous volume of publishing lately in children's books," says Darlene Daniel, the association's president. "Publishers have awakened to how responsive parents and children are to fine writing and illustration. Everyone wants to break into the field."

The society offers a variety of benefits for members, 1,200 of whom belong to the Southern California chapter:

* A free manuscript exchange allows members to exchange writing and illustration for analysis.

* How-to information is available for cost of postage. Subjects include manuscript formatting, authors' rights and responsibilities, copyright facts and small press markets. An annual survey of what publishers search for also is available.

* Members receive two publications. The bimonthly national "Bulletin" details writing trends, contests, tips from publishers, market reports and events. "Kite Tales" is the quarterly local chapter newsletter.

* Grants, totaling $8,500 a year, are given to members who have fiction and nonfiction works in progress.

* Medical and life insurance are available at reduced rates to members through a group plan.