I had meant to touch on the specifics of actually submitting in my previous post, but it all got away from me. With this one, I'd like to suss out a few of the particulars, which I had to do some research about early on. Hopefully this will help out a future submitter later.
Multiple Submissions Vs. Simultaneous Submissions
Typically defined, the term "multiple submissions" means several unique submissions to the same journal, review, or publication place at the same time. During the course of my exploration, I've found a small number of places that accept multiple submissions. I imagine this is due to the fact that some writers simply can't help themselves and want to send a deluge of content to a place and see which they like. The problem with this is that it creates a mountain of submissions for editors to sift through. Especially considering how the next phrase works.
"Simultaneous submissions" is a term that means a single piece can be submitted to multiple places at the same time. More publications are open to this as long as they're notified when the piece is published elsewhere so that they can remove it from their own consideration pile. You can see now how the confluence of both multiple and simultaneous submissions can be problematic; submitting the same ten pieces to ten different places might up your odds of something being published, but it overwhelms and gums up the works all across the board. To say nothing of the fact that you'd have to go back and contact each of those publications if one story got published, much less all ten, a very small likelihood in and of itself.
Submitting Novel Excerpts
This one's tricky. Some places accept novel excerpts, but most don't. Why, you might ask? Because there are very few chapters of most books that don't require the chapters before and after it to make sense of the one in question. Even better, remove a chapter from your book. How does the removal of that chapter change the narrative flow of the entire work itself? If the change is so drastic as to make your book unreadable, then obviously you can't submit that piece for standalone publication. A general rule of thumb for my own personal use: don't submit novel excerpts, even if a publication accepts them on principle. It's highly unlikely the piece will make much sense without the corresponding chapters and if you're a writer, then you know you've got other pieces to submit.
Submitting Near/Around Due Dates
The vast majority of publications have cutoff dates for when they stop reading and considering submissions. I don't have much in the way of knowing how much more quickly a publication will make a decision on a piece the closer it's submitted to the due date. Personally, I try to submit a week or two before the due date, hoping I will end up hearing back on the piece sooner. But, it's just as likely that you'll hear back quickly if you submit early on when there's not such a wave of submissions coming in all at once. Perhaps the middle ground of submitting at the halfway point between the open submission date and the closed submission date is your best bet here.
Contacting a Publication on the Status of a Submission
So your piece has been out in submission land for five months. You've heard nothing back from the editors and you worry that they've somehow forgotten about your piece (because your piece being published is the most important thing...to you). Wait another month. Most publications that I've come across have blatantly stated "do not contact us about the status of a submission unless it's been over (x) number of months." Six months is usually the accepted length of time. Anytime before that and you may find yourself either blacklisted from that particular publication or have your submission summarily rejected. These are obviously worst-case scenarios, but it can happen. Don't be a douche; stay patient.
Paying to Submit
I used to only submit to places that were free and didn't charge a dime for anything; not for reading, not for editing, nothing. Now that most publications have gone to digital submissions, a few have begun charging reading fees. At first this bothered me, but more and more I realized how much paper these places were probably using to print up who knows how many submissions, so their costs were probably ballooning a bit. Since the writer wasn't submitting hard copies via post, this meant more costs in printer ink and paper. And a lot of places only publish digitally now, trying to keep their costs down while still trying to find that writer/writing that they want to highlight in their publication.
Most places charge just a two or three dollar fee to submit. This is completely reasonable. There are a few others I've seen that have charged upwards of $30, but this fee includes a deep critique of the submitted piece mailed back to the writer with notes on the manuscript. I won't say that's a high fee, but if you're just starting out and haven't had anyone look at your work before, try one of these once or twice to get a feel for the process. Each editor will read a piece differently, so it's good to get an in-depth look at your work whenever possible. Bottom line: fees are okay. Don't be afraid to pay them on occasion, but there are certainly plenty of other (free) places out there.