I read the unsolicited pile for a variety of agents, and one of the markers that gets a submission pulled from the rest, and given a little more attention, is previous publishing experience. My clients are looking for anyone who has had a short story published, who writes for a newspaper, or has written books in a previous context - even in a different genre.
There are two reasons for this, one is that the author has already got experience of 'how' to be published, they have an idea of the editing process, of the demands on an author and an editor's time. The second, and more important reason is that the author has already been quality controlled. Another professional has judged the author's work to be publishable.
If you feel that getting published in a magazine or local newspaper is beneath your ambitions, think again. This list is of the top ten authors who were published in Playboy magazine, for those who really did buy it for the articles!
Cressida
(Editorial Consultant)

Freya Morris on February 8, 2011
Strange, I have currently been thinking this was the case, so am focusing my efforts on trying to win some competitions. I don’t feel my journalism experience is quite cutting it as it’s mainly web based.
Would perhaps making it stand out in my covering letter help? Or perhaps going into more detail than just stating where I’ve been published?
A fascinating link to the playboy authors, I had no idea.
Neil Ansell on February 9, 2011
I spent several years working in journalism, both as a freelancer and a staff journalist, and it definitely helped me learn the craft of writing.
And the deadlines and wordcounts, the dealing with editors and sub-editors - these all help in your approach to creative writing.
Nyika Alexander on February 25, 2011
I'm a bit confused by this whole thing. The publishing houses won't take your submissions as you need an agent but then some of the agents state no unsolicited manuscripts so how does this work??
1Mark Rudd on January 3, 2012
Guidelines seem to vary widely on what an unsolicited manuscript actually is, and how to get it, er, solicited.
Debora Lucken on January 12, 2012
thank you for sharing this piece of information. I feel more motivated to get my stories out there. Actually, I don't think is about motivation, but more like fear.
I like the list and I found particularly interesting to see Roald Dahl in there...