...read the submission guidelines. I had to reject a full 1/5th of the stories I slushed today because of submission guidelines violations. It wastes my time and makes you look lazy.
...avoid using strange formatting, or odd fonts, or variations in the spacing between paragraphs, or... I could go on all day. How your manuscript LOOKS does make a difference in how I FEEL about it. If it looks neat and clean and professional, I'll treat it with a great deal more respect. The vast majority of the stories that end up being published are neat, clean, professional-looking manuscripts. People who care about their writing show it by the care they take preparing their manuscripts.
...proofread your story with your own eyes--or better yet, someone else's. Don't rely on spelling/grammar check software. One or two missed minor errors is not a big deal. It happens to everyone--even the pros. But a lot of errors in your manuscript makes me think you don't take this writing thing as seriously as I expect you to if we're going to pay you for a story.
...don't submit stories told from a cat's POV. (OK, that ones mostly a personal preference. Mostly.) ;-)
I am very happy to follow submission guidelines and make a neat presentation, but I have seen some that are outrageous. There are so many details and they make it sound as if you don't get it perfect they're going to reject you automatically. I feel like I need to stand on one foot, rub my stomach and pat my head while I hit the send key.
I have to admit, when I come across these it sounds like a very uptight publication and it's doubtful that they're going to like my stuff if that's the case. Often I just look harder to see what other, more reasonable, publisher is willing to look at my work.
If I think it's a worthy market I will jump through the hoops. But I find it interesting that the professional publications seem to have very standard and reasonable guidelines and don't try to make it difficult at all.
One recommendation I could make is, if you choose to submit in the body of the email, turn off smart quotes, and be sure it's otherwise formatted properly. It can be very difficult for editors to follow your story if the paragraphs are out of order and the quotes have all been replaced by question marks.
Regarding outrageous submission guidelines, the major markets do not have them and most semi-pro markets do not have them.
If a market that pays a pittance wants me to deviate from standard format other than minor tweaking or a simple file format change, I send it elsewhere. It's not worth my time to comply with weird formats because there are plenty of markets that don't make you jump through non-standard hoops for the great honor of appearing in an obscure market that almost nobody reads.
You can't go wrong following proper MS formatting guidelines as a standard.
Then from there, a few pubs may ask for a slight variation, which to me is completely fine (e.g., WOTF which requires that you remove your last name from the pages of the story after the title page.)
But I have encountered plenty of people (particularly young people) who think that adding cool fonts or colors makes their work look better. I think that energy would be better spent in designing covers to their work that they can use when they choose to print and bind it themselves. Let the story stand on its own. Decorate the wrapper.
But oh, the proofreading! Read your stories aloud if you're not already doing this. All the way through. Just circle spots where you have trouble/notice a problem, etc. Don't rewrite, keep reading just red pen the MS for the issue you noticed and keep moving. I wish more people did this, as I don't think they realize how clunky things can sound, or notice typos that are misused words to/too/two, there/their/they're. Reading aloud forces you to consider each word more carefully and you can find many, many of your own errors this way. (And yes, people submit with errors all the time and still get published, but someone who submits with several errors that should have been caught in the editing cycle looks sloppy. Don't we all want to put forth our best impression?)
I'll add my personal pet peeve: Don't deviate from standard points of view unless you A) Have mastery of POV, and B) Have a compelling reason to tell the story from that POV.
Second person is a really weird point of view choice. I have seen it handled inexpertly dozens of times. Expertly, only once or twice (when it's been done expertly, the result is that you--the reader--really experience the emotions and the feelings the author is trying to convey at a level much deeper than usual for a 3rd/1st person POV. You don't even realize it while it's happening to you. You just leave the story, you realize that you feel these things. You normally hate the idea of each sentence being a directive statement, but you adjust your way of thinking and identify ways in which you can change and grow from your interpretation of the work...LOL)
2nded, by Editor Pyre. (Except the cat part, I enjoy cat fiction. Started writing one myself.)
I once got one with this paragraph out front (which, by the way, was the only one in the whole piece actually formatted correctly) that told me how important the formatting was, all before the title. And then what followed was italic, underlined, bold and in a particularly fruity font (if I remember right it was harrington.) The slap in the face at the beginning (especially since I was doing the typesetting on this particular edition) made me feel good about tossing across the room without reading it.
I do what I can, but if I follow the Letter of the Law I might never submit anything anywhere. I'm barely hanging in there right now.
But (as some of you have heard me sing the blues about before) a lot of places have requirements that seem a little iffy and demanding, considering the circumstances. Pecularities about typefaces and the paper it's printed on come to mind.
Plus if a MS is rejected for that kind of reason, it's often not said---like, "I am rejecting your manuscript for reasons I cannot say." (Even in a form letter.)