The "Things I've Been Asked Lately" series of posts (TIBAL) is exactly what it sounds like. People ask me questions in real life, on the blog, or on the forums I follow and I endeavor to do my best to answer them. This is, of course, all IMHO.
How Many Short Story Submissions Should I Have Out At Once?
As many as you can juggle.
Whenever I get asked this, people seem to have expectations that there is a magical number to aim for. Often they expect it to be ten. Sometimes four. And as best I can tell the number correlates with the amount of time they've invested in writing for publication.
The number of stories you can keep out, of course, depends on the number of pieces of fiction that you have finished and ready to be published. Not sort of ready or close to ready, but ready to go to print right now. Magazine editors do not make substantive edits; they are content seekers. They will copyedit and they will occasionally make edits to the prose or story (and often the title), but they'd really rather find work that doesn't need all this extra tweeking so that they can get back to their families and work at their paying jobs.*
[*Magazine editors are rarely ever paid for their work.]
In an ideal world, you only submit to magazines that you have read several issues of.
I say the ideal world because, honestly, I do not have the time or the money to subscribe to that many journals and read them all. I choose a couple each year to whom I give money for a subscription (often coupled with a contest fee), and I occasionally browse online content.
What I try to do is that whenever a rejection letter (or email) comes in, I take a look over the story and then send it out to one to three other markets. You can see how this tends to increase the number of submissions out. For a while, I would keep upwards of thirty-five submissions out between five stories and three poems. I let this slide at the end of last year and now I have 11 submissions out between three stories and one poem.
Whatever you do, you need a damn good way of tracking all this.
I have a two-fold approach. First is the submissions tracker on Duotrope.com and the second is a three ring binder that contains a sheet for each story title. On the sheet I have marked possible markets, (then when it gets sent) a date next to the actual market, and a big fat line through it when it comes back with a 3x5" slip of paper.
I will say that it used to be a lot more work to keep multiple story submissions out. Now many of my submissions have never touched an envelope. I go to a magazine's website, use their database uploader, type in all my information and send off the story with a click of the mouse. If I've sent them the wrong copy of a story, I can just withdraw it, also with the click of a mouse. Even those magazines to whom I'm sending hardcopies have fairly streamlined processes: I can find all their wants, desires, open reading periods and contact information right on their websites. And websites like Duotrope.com organize the magazines so that I don't have to sift through webpages in a Google search to find the right one.
So much easier than using the four inch thick Publisher's Market Place. (Yes, I did used to use that. Research with it took days.) Although I hear they have a CD/computer version now. But I never used the copy that came with a CD because I always checked mine out from the public library because of the expense.