Although I'm not world-renowned, I've been around the block a while in the writing world. I've learned little things along the way that may help others as they begin their foray into writing and hunting for publishers. I'll try to post more of these as I think of them or as certain questions arise as I surf around the Internet.
Most magazines are good about getting back to you, but I have had my share of no replies, or I'll get a subscription form in the mail and nothing else. Then I'm not sure if I'm just on their mailing list now, or if that was supposed to be a rejection. Also, things change quickly for publishers and I would suggest checking websites before sending something out just in case something has changed. The Writer's Market guide will say one thing, but you'll find that the guidelines on the website say something different.
And just because a Christian publication accepts short stories, don't assume they accept fiction short stories. To me, short story means fiction, but it must also mean a true story that is short. Beats me, but I've run into that.
The best advice I can probably give is pick a publication you're familiar with or read a lot of issues of one and write a story with that specific magazine in mind. The artist in me cringes at that, but I've done it three times and all three were accepted on the first try.