Everything op-ed (opposite the editorial; opinion, commentary, etc.) related can be found on The Op-Ed Project’s website.
Washington Post’s Opinion editor, Alyssa Rosenberg explains what makes a good opinion pitch in this Twitter thread.
Read guidelines on how to submit an op-ed essay to the New York Times here.
Guidelines on how to pitch an article to Guardian Opinion here.
How to submit an op-ed to The Boston Globe here.
Write first or pitch first?
Depending on where you pitch, you might be expected to submit a full draft before an editor gives you the green light. Having written a few op-eds that never saw the light of day for prestigious publications (in one instance, twice for the same editor), I now advocate against writing op-eds on spec (that is, submit a draft on a speculative basis).
I would argue that this is especially true if you’re an established mid-career journalist and have a set of clips. I know a lot of bigger publications, especially those based in the US suggest a completed draft is the norm, but, to me—an Indian writer based in India—it seems like a step in gatekeeping a number of already overworked and underpaid freelance voices.
Here are a few publications that (at least in my* experience) let you pitch first-
The Independent’s Indy Voices
CNN Opinion
Metro Opinion
South China Morning Post
The Daily Dot
HuffPost
The Guardian
Bustle
Glamour
Lacuna Voices
Pitching a argument before you’ve got a full draft down also lets the editor talk through the angle and the story with you. Perhaps there’s an overarching theme they want you to include. Perhaps they’re not interested in that particular angle, but something else you mentioned in the pitch caught their eye.
Also read Nicole Dieker’s take on this in “Ask a Freelancer: Should You Write Your Article Before You Pitch It?” for The Freelancer by Contently.
*disclaimer (because this is the internet): This is just my experience