Matt
I think my favorite place to submit was Asimov's from its start in the seventies to the mid-eighties. They used to put a postcard with a few notes about the story on it---I learned a lot from those comments. (The guys editing Asimov's moved on to Amazing for a period right after, continuing their practices.)
One of the reasons I "took" to Internet Fan Fiction was my getting tired of all these form letter rejections. It was like writing in a vacuum---I didn't know if anybody was reading my stories, much less what they thought about them. So I suspended my attempts to get published for, oh, about four years, total. In the end, I got more feedback and reaction to those stories than anything I've written for publication. I'm taking what I learned there and applying it in another attempt to get something published. (But my standards have shifted some, and, though I've written a fair amount, I've only sent out three or four stories since restarting this effort.)
Let's carry the baseball analogy over to submissions and results. Submitting a story is like going to the plate. Real baseball fans know there are three outcomes of every plate appearance: you get a hit, you get out, or you get out but have a great at-bat in the process (which means getting the pitcher to waste pitches).
Does not the same hold true for submissions? You either get rejected, or get accepted, or get a personalized rejection letter. Now in baseball, good hitters -- those going to the hall of fame -- bat around .300, which means they strike out 70% of the time. Would it not be a good idea for a beginning writer to accept striking out 70% of the time? Some of those strike out are going to be just that -- strike outs. But some will prove to be good at bats; that is, the personalized rejection letter. Regardless of how you look at it, rejection in writing is the norm.
The analogy can continue. Just as baseball has the Minor League as well as the Major League, there are pro sales, semi-pro sales, and just paying sales. You might be fanning on everything you send to the pro markets, but might be getting good at on the semi-pro level, and even getting hits on the paying level. Very few writers, just as very few baseball players, start out in the Major League.
This is just another way of saying what Isaac Asimov said, namely, writing is like school, and you need to send your stories out so that you know when you've graduated.
At any rate, this is how I look at it, and it's given me a quite a bit of peace about the daunting experience of putting my stories on the market and keeping them on the market until sold.