This is very important to know if you intend to submit your work for publication: most magazines and journals do not take previously published material. If the submission guidelines say "first publication rights" or similar, it means that they will not accept work that has been published elsewhere, including work that has been self-published. Wattpad, tumblr, personal blogs and websites count as "previously published". If you want to submit your work later, do not post it on a public website or blog!
Rejections are just part of the game. You can't be a writer without a thick skin, and there are countless stories of famous books that were rejected dozens of times before a publisher finally took a chance on them. Students should know not to feel discouraged by rejection letters, many of which might be a "form" letter that doesn't include feedback about their piece.
Students who are used to getting their assignments back after a week or two may balk at common response times - a month is considered "fast" and some journals can take close to a year to send responses. It's worth warning in advance that it may take quite a long time to get even a simple "no thanks" email. Most (not all) of the markets on this list respond within 3-6 months.
A simultaneous submission means that you've sent the same piece of writing to more than one place at the same time. It's a common practice, because of long response times, and many journals don't mind it so long as you tell them immediately if the piece is accepted somewhere else. Check individual submission guidelines to see if they allow simultaneous submissions. If your work is accepted at one of several places you submitted to, the polite practice is to immediately withdraw it from the other journals - don't send any "Journal X wants to take this story, would you like to make a counter-offer?" type emails; it is considered incredibly bad taste to have a piece accepted somewhere only to turn around and tell them they can't have it anymore.
A Note About Pay
Literary journals are mostly staffed by volunteers and unless they have a lot of paid subscribers, running costs tend to come from the editor's back pocket. This means that there are a number of quality journals out there that cannot afford to pay contributors, or only pay a token amount (e.g. $5). Higher pay does not necessarily mean more readers - things like government grants, fundraisers etc can impact pay rates on offer - but as a general rule, the higher the pay, the harder it is to get a piece accepted. Some journals also run competitions with prize money or offer additional pay to a "best of" each month or year. To my current knowledge (September 2015), none of the journals below charge a fee to submit work or enter competitions.
And with that, here's the list:
Voiceworks is a quarterly Australian literary journal that only accepts submissions from writers under the age of 25. It is exclusive to Australian writers and International Students who are currently studying in Australia. They accept fiction, non-fiction, poetry and art and pay $100 per piece. Voiceworks is committed to helping young writers grow and they send specific feedback to every piece they receive.
Vine Leaves (http://www.vineleavesliteraryjournal.com)
Vine Leaves is an Australian based journal dedicated to the vignette, a short form of writing that differs from flash fiction in that its focus is on an element such as mood, character or setting, rather than plot. The journal has a "Blooming Vine Leaves" feature for writers aged 12-17. They pay $5 AUD per acceptance into the journal.
Spine Out (http://spineout.com.au/)
Spine Out is an Australian website aimed specifically at a YA audience (12+). All work published on Spine Out is from school students in Australia. They accept creative works of all kinds, including fiction, non-fiction and poetry, but also music videos, cartoons and short films. Issues are published (posted online) every 2 months. Contributors are not paid.
Ember: A Journal of Luminous Things (http://emberjournal.org/)
Ember is a US-based literary journal aimed at fostering a love of reading and writing in young people. Their website states that they accept work for "all age groups" but strongly encourage work from writers aged 10 to 18 and writing for a middle-grade or young-adult audience. They accept poetry, short stories, flash fiction and creative non-fiction. Ember pays 2c per word or $20 per piece, whichever is more. It is published semi-annually. The majority of their responses are "personal" (i.e. with feedback).
One Teen Story (https://www.oneteenstory.com/)
One Teen Story is a US literary magazine that publishes one story per month. Of the twelve stories published in a year, four are from teen writers. They accept short stories between 2 500 and 4 000 words directed at a Young Adult audience (13+). They pay $500 but only accept one story a month, so competition is fierce.
Cicada is part of a "family" of US-based literary magazines aimed at different age groups, the best known of which is Cricket. Cicada is the Young Adult member of the family and takes submissions by writers aged 14 to adult. From time to time competitions are held specifically for young writers (i.e. adults over a certain age cannot enter), but it is unclear whether Australian writers are able to enter these. Pay varies, but their rates for general submissions are some of the highest I've seen. Cicada accepts non-fiction, fiction, poetry and comics.
Young Adult Review Network (http://yareview.net)
Another US-based journal, YARN is aimed at Young Adults 14 and up and accepts work from writers of all ages. They are looking for poetry, fiction, essays and interviews. YARN is published online and does not pay contributors.
Cast of Wonders (http://www.castofwonders.org)
A UK-based podcast website, Cast of Wonders targets a 13-17 year old audience and specifies in their submission guidelines that they are interested in work from younger writers. They pay £5 per story, which they then post as an audio reading in 20-30 minute "episodes". They are seeking writing between 3000-4500 words in length but do accept shorter works and work up to 7500 words.
Other journals that do not specifically request young writers, but have been known to publish them:
- 50 Word Stories (http://fiftywordstories.com) - a collection of stories written in exactly fifty words.
- Inscription (http://www.inscriptionmagazine.com/) - a fantasy/sci-fi young adult magazine
- Smokelong Quarterly (http://www.smokelong.com) - a weekly online journal for flash fiction up to 1000 words
- Rattle (www.rattle.com) - a poetry journal
- The Adroit Journal (http://www.theadroitjournal.org) - a fiction, poetry and art journal that also runs an annual competition for high school and university students