Short story markets

Analog, Asimov and F&SF are generally considered the top three spec mags.
Go to Duotrope or Submission Grinder and it will list all the pro markets, semi-pro, token and non-paying. The pro markets are obviously the most desirable.
Good luck!

Ralan.com is another place that lists markets in categories. The list the number of words, turn around time, what type of stories they want, and pay also.

You can decide if you want just pro pay or almost pro, something or nothing. I believe most pro and semi-pro markets are worth trying for.

I would rank the markets more like Clarkesworld (10 cents a word and lots of award noms), Lightspeed (5 cents a word, lots of award noms), Asimov's (6-7 cents a word, lots of award noms), Analog (same as Asimov's), etc.

Personally, I send out based on pay, so for me it is Clarkesworld, Daily Science Fiction, Strange Horizons, etc on down.

I try to eventually send each story to most of the markets that pay pro rates (5 cents a word), but various factors affect which markets I send to first, such as: whether they liked my previous stuff, prestige, whether the market routinely gets reviewed in Locus, turnaround times, pay, convenience (e-submissions), and the likelihood of getting feedback. My stuff also tends to exceed 6000 words, so that limits my choices as well.

Typically the first markets I send to are:

Clarkesworld
Lightspeed (if open, usually not )
Asimov's
Strange Horizons

Some other things to consider:

From what I understand, the big three (Asimov's, Analog, F&SF) have 15,000 to 30,000 subscribers each, plus they sell a fair number of individual e-copies. It's not usually clear what kind of readership the other markets have, but it will probably be much less than this. The amount of people who will actually read your story might be an important consideration for some people.

There is something to be said for having your story reviewed in Locus. If Lois Tilton at Locus likes your story, you might have a better chance of reselling the story, being nominated for an award, and/or making it into one of the "year's best" anthologies. There are currently several pro markets she just doesn't review, while I believe she does review a few semi-pro markets.

Clarkesworld actually had some statistics in this month's Editor's Desk column. They have around 2,700 paid subscribers, 6,000-7,000 podcast listeners a month and an estimated (they say conservative) 33,000 monthly online readers.

A lot of factors go into submissions for me, I guess. CW is my favorite magazine because my taste seems to sync up pretty well with Clarke's. Asimov's, prestigious as it is, rarely does much for me. Because of that, I think a Clarkesworld publication would mean more to me. And 10 cents/word with a turnaround of a few days certainly doesn't hurt.

Odds are slim, but when you are debating a never-going-to-happen with a three-day response time against something more practical with a 60-day response time... it doesn't hurt to dream, right?

I think you should always start at the top and work your way down the list. For me, payment is the foremost factor -- not because of the actual amount of money, which is very small anyway even for the top paying markets, but if you want to become a professional writer you ought to consider first the markets that pay the most. Having said that, I've still never submitted to Tor, because response time is also a big factor.

Also, sometimes I write in response to themed anthologies (or themed-issue magazines like Penumbra or Crossed Genres), in which case I submit there first (well, unless I miss the deadline ),

F&SF doesn't exist for me, because I've made a vow I'll never submit to a market which doesn't accept electronic submissions -- I can only afford paper submissions in Greece.

Analog and Asimovs accept only SF stories, so I can't send them everything anyway.

To summarize, my most-submitted markets so far are (thanks to the Grinder and its awesome stats):

Clarkesworld 11, Daily SF 11, Strange Horizons 11, WOTF 9 (out of 9 quarters so far), Lightspeed 7.