Professional writers for children belong to the Society of Children's Book Writers and Illustrators - SCBWI. To become a Full Member, you have to have had a children's book published.
Editors receive manuscripts from authors and all kinds of 'wanna be' writers, and can get jaded reading dozens of unprofessional letters and stories with no potential.
Even finding out about the Society and paying the fee to become an unpublished 'Associate Member' shows that you are serious about the craft, and many Associate Memebers have had books published for adults but not yet for children.
After considerable recent discussion amongst members of the Yahoo Children's Writers forum (thanks everyone for your input and advice!), it was generally agreed that:
By mentioning SCBWI on the outside of your submission envelope, whatever level of your membership, you give an editor an expectation that the contents will be professionally presented and could be worth reading, and may just encourage them to spend a little extra time considering what you have written - enough to make the difference and eventually send you a contract to sign. Before joining SCBWI, writers at least will have probably had professional tuition through a course, and the chances are that a member will belong to a critique network and have worked on their manuscript for a considerable time and noted the insights and advice of their writer buddies.
If a member, it is suggested that you write in the bottom left-hand corner of your submission envelope:
or, if the editor gave a presentation at a SCBWI event and said they would read material from attendees:
Attendee July 2006 Queensland ConferenceOf course, the envelope could just be ripped open by an office worker and discarded before being read by an editor, so I usually put something about SCBWI membership early in the cover letter too.
If you are a serious about writing for children, I suggest you research and join the Society.
(You're still allowed to give your manuscript a hug for 'good luck' as you drop it in the mail! Luck can always play a part in acceptances - but you might find my cover letter recipe useful too.)