Look through magazines like Writer's Digest that list writing competitions and publications in the back of each issue. Find online contests or publications, which may or may not pay for stories.
Before submitting a story, check the site to make sure your style matches the genre of the online journal. Compare similarities or differences in writing voice, themes and points of view.
Determine if the journal will accept multiple submissions so you may send several different stories. Also check if the journal has a policy against submitting your work to different companies. Notify the journal if your story has been accepted elsewhere.
Write a cover letter that explains why you feel your short story belongs in the online journal. Include details on your writing experience, past publications and perhaps a link to your online portfolio.
Create an online portfolio or blog to showcase your work and your daily writing. You can create a simple website for free using various sites like weebly.com or a free blog using wordpress.com or blogspot.com. Use these sites to network with fellow writers, who can recommend paid online journals.
Take rejection lightly. It happens often. If you receive one of those dreaded (but frequent) rejection letters, respond with thanks and ask the editor for feedback or to recommend a place likely to publish your work.