Look up the requirements for publication with the newspaper, magazine or publishing house you're interested in. If no guidelines are available online, call the publication. Some children's publications include Highlights Magazine, Pockets Magazine and Cricket Magazine.
Revise your story to meet the requirements of the publication in question. Highlights Magazine, for example, requires stories to have no more than 800 words for children ages 8-12 and a maximum of 500 words for children ages 3-7.
Get to know the publication in question before sending out your short story. Read a few back issues or prior publications. If your children's short story doesn't seem to fit within the general style or usual content of the magazine, this may not be the publication for you. For example, a children's short story with a Christian theme would be better in Pockets Magazine than Highlights Magazine, which has no religious affiliation.
Send your children's short story to the publication as requested in the writer's submission guidelines via postal mail or email. Double-check to make sure you've included your contact information, query letter and a complete manuscript, if requested.
Don't call the publisher to check up on your submission. Because of the number of submissions received, especially at national children's publications, not all publishers will or can advise you if your submission is refused. If your submission is accepted for publication, you will be notified.
Continue submitting and editing your stories even if you receive some rejections. Send a query letter or talk to local newspapers and publications about the possibility of publishing some of your short stories for local children.