Do aim to make your cover letter as professional as possible. Study examples online. Be respectful and courteous. Don’t worry about trying to be super-creative in your letter: Your work is where your creativity will shine. A forgettable letter is preferable to an unprofessional or over-the-top one.
Don’t forget to tailor your letter for each publication. It’s smart to have a basic template, but alter it slightly depending on where you’re querying – even if it’s just including a specific name instead of “Dear Editor” in your opening.
Do mention if a recent story, poem, essay, or other piece published by the journal resonated with you.
Don’t go into too much detail explaining the work you’re submitting. Trust in the strength of your work to speak for itself.
Do mention where your work has been published elsewhere, including forthcoming bylines in future publications – just be sure to indicate that they’re “upcoming” or “forthcoming” when you mention them. That said…
Don’t let your bio intimidate you too much if you are new to publishing. Many editors choose to read the submission first and the bio second, so they won’t be unconsciously biased by an author’s credentials. Editors love discovering new voices for their pages. Remember, too, that it’s just as much of an honor for the publication to host a writer’s first-ever byline as it is for the writer to receive it.