Fist of all here are some things you're going to need on your quest to find those guidelines:
possibly a few bucks
Yep, all of that, and did I mention patience? Um, yeah, that kicks in when you realize how much time you're wasting (well not wasting, but certainly how much of it is flying by) when you undertake this project.
For starters yes, visit the website of a publisher you're interested in. Poke around a bit. They call their guidelines a variety of things. Sometimes they’re located under “Write for Us” or “Submissions”, or “Submit a Story”. These are the easy ones. If you don’t see an out and out link to guidelines, visit the ‘about us’ section and see what you can dig up there. That’s where I’ve frequently found the submission information link. There are times when you swear they want to make it like a treasure hunt.
Beyond that basic first step it’s amazing the kind of wild goose hunt publishers seem intent on sending you upon just to locate their contact information. Now, some writers claim they’re testing us, trying to see if we’re lazy or not and if we actually locate their information then, wow!, we’re not lazy after all. Or, some say, the publishers are testing us, trying to find out if we’re persistent enough to uncover the guidelines and if we are then we can research assignments. I’m not sure I buy either one, but the fact remains, it can be a real headache to locate them.
Then there are those, I swear, that you’ll never find on your own. I’ve spend amazing amounts of time pouring over sites only to be defeated. Either they don't want to put their contact information and guidelines out there on the web or they have a very inept web designer. Whichever..
So here’s another approach. You can subscribe to writer's market online It’s about $5.99/mo. last time I looked and it’s very handy, online, at-your-fingertips information. If you prefer the actual book you can peruse that at your library or purchase a copy. Amazon usually has it at a good discount. And if you get the Deluxe edition for 2012 you receive a year's free subscription to the online edition which would be worth $72 on it's own. I'm not pushing it, but it would probably worth your while to plunk down that money and get your own copy. But, if you're stone broke, the library certainly will have a copy.
Amazon also has the “American Directory of Writer’s Guidelines: More than 1600 Magainze Editors and Book Publishers Explain What they are Looking for From Freelancers” by Stephen Blake Mettee, etc. - I've used it but unfortunately the latest edition is 2006. You might have to search for a newer edition, if there is one. Or you can check it out at your local library. A lot of the info would still apply.
Those are the basics. Get out there and start tracking them down. But, as you poise ready to do this, remember:
Bookmark your sources once you find them.