More on marketing your work today.
I would rate Guidelines as one of the most important elements of the marketing process. Some publications have lengthy, detailed guidelines while others are very basic, almost nonexistent. The long guidlines may at first appear overwhelming, but they are going to benefit you far more than the puny ones--or even none at all. When you send your work to a publication that provides no guidelines, it's frustrating. Much uncertainty as to whether your story is going to be appropriate for them.
The editors have specific needs and wants which they pass along to the writers through these guidelines. If you read them carefully, then work at meeting them, you'll have a far better chance of acceptance. Take a look at the Guidelines page at the Chicken Soup for the Soul website. It's pretty specific. The editors tell you not only what they want but also what they do not want. I hear over and over from writers who say they submit to Chicken Soup all the time and have never been accepted. I can't know the exact reasons their stories did not end up in a book, but one of the reasons might have been that the story they sent did not adhere to the clearly spelled-out guidelines.
Now look at the Guidelines page at Knowonder! children's online magazine. Their editors have given you a choice. They provide both a short and long version of their guidelines. The longer version is one of the most detailed I've ever seen, and yet, I'm sure they receive submissions that absolutely do not fit the parameters of those guidelines. You not only have to read them, you have to adhere to them!
I was asked to submit a devotion piece to a Parish Nurses group last year. It was to be relatively short so I thought it no big deal. When the nurse who had asked me to contribute sent the guidelines, I was amazed to see that they were exceptionally detailed, even down to the font size to be used for scripture quotes vs the size for other parts of the piece. Some of it was to be in Bold while other sections were not. A certain number of spaces between title, sections etc. And on and on. It was an international publication with many who read it using English as their second language, so I think the editors wanted it to be in the same format for each issue to make it easier for these people.
Contests nearly always have specific guidelines. If you don't follow them, your submission will be tossed out immediately. I always read the guidelines, try to do all they say, and then go back over my submission with a checklist. I would hate for my submission and entry fee to go sliding down the tunnel of rejection because I did not meet the required format.
Don't just scan the guidelines. Study them! If you submit several times to one publication, their guidelines will be more familiar to you. Do continue to check them each time, however, as something might have changed.