Another strategy for your short story is to make it free so that others can discover your work and lead readers to your novels. Tricerotops did this with a short story prequel and can give you more information on whether or not this has been beneficial.
Yeah, my publisher suggested I write a prequel short that ties into the novel. I don't know where he got the idea, but he must have been studying Amazon or reading Konrath or something. Since the novel was a space faring adventure, where the crew performs "missions", it was an easy concept to grapple with and produce. He called it our "sacrificial lamb", because he intended to list it free as many times as we were allowed--something like five times or so in a 90-day period? I forget the maximum free download times. Then he would switch it over to a .99 price point and let it hang by its neck.
Our first free trial pulled about 350 takers, not a real big number. But after it went to cost (.99) the book sales spiked in the top 100. Sales started rolling in. When book sales started leveling off--he list the short free again. Boom. Spike.
He tried changing the book price from $1.99 to $2.99 then back again over a period of couple of weeks. Another small spike. Then he offered the
book for free (over a weekend, I think), and when it came back on cost, it hit another rank spike. So he staggered the free trials between the short and the book back and forth, until ultimately our free trials were used up. But the short started selling all by itself, something like 1 to every 4 books, which was kind of a pleasant surprise. Imagine your short having a slap-fight with your novel for position!
Just in the last 13 days we've had something like 85 sales between the two, the majority of them books. Nothing to write home about, until you consider that the book came out in hardback first and flat-lined after three sales over a period of 11 months. Absolutely terrible. Since the book went e-book three months ago, and the short was put up only a month ago, it's sold hundreds of copies. We're still waiting on Kobo and some other online vendor numbers.
So, yeah, a tie-in short to your book makes things really happen. Seriously, I don't/won't pull the money that a self-published author does because I split the proceeds with my publisher. But still...
I went right to work on the second short and just turned it in. My publisher will edit it, format it and publish it on Amazon. Then we'll do the "stagger" thing again. Honestly, I think we can produce and list about five to six more prequel shorts to milk the Amazon system for everything it can give us. Then comes time for the real work--the full length sequel. Wash, rinse repeat.
I couldn't tell you what a standalone short would do. Just experiment and stagger the free trial periods. My first short was 6,500 words, and this second one is 8,500 words. I don't think I would go any lower than 5,000, just for personal reasons.
Did this help my my other genre trade and e-book sales? Nope. My paranormal romance picked up one sale through all this. So from my perspective, not many readers will check out your other genres unless you're pulling some huge sales numbers. I've pigeon-holed myself in SF for the time being.
I'm mini-me compared to Nick, Merrihiatt and others who really have the formula down pat. Check them out in the other threads, particularly "Share Your Successes." I'm very late to this game--even my blog is brand new, trying to catch up with all these others. But I do market-slut myself every day--places like here in the Blogs thread, FB, Twitter, LinkedIn, Book Blogs, all those damn YADS sites, and as many interview and review blogs as I can participate in. My next stop is smashwords and Goodreads--I know absolutely nothing about them, other than they are hot promo and marketing sites.
How long does it take to build up inertia and see good results? In my case, it took three months. YMMV.
Tri