Writing Excuses - Writing Excuses is a podcast geared towards writers of Science Fiction, Fantasy, and Horror. The cast consists of published novelists who share their insights on many different aspects of the craft. From the painstaking details in creating sustainable and believable flora and fauna in fantasy worlds to how to write endings, no topic is too big or too small. Every week they have a recommended audiobook from Audible (their sponsors) and a writing prompt. Sometimes they even have brainstorming sessions and then give away the resulting ideas for free. At 15 minutes long (at most, 20), it's a quick and painless listen. I tune in weekly.
Duotrope - An invaluable resource for anyone wanting to sell short stories, Duotrope allows writers to search for publications by genre, pay rate, publication type, and length. It includes aggregated stats from users which give an idea for average response times, rejection rates, and what not to do when submitting. How I use it: I search for my genre with the pay-type I'm seeking, go through all of the results, compile a spreadsheet with the relevant information, and then go back to assign different stories to the publications they match up best with.
Critters.org - Another gem for writers of SF/F/H, this is a great place to receive critiques of your work. Like Scribophile, the site is member only. Every Wednesday, the owner releases about 20 manuscripts (short stories up to 20k words) and people have a week before the next batch to critique at their leisure. To make sure people do their fair share, users have to maintain a 1 critique/week of involvement ratio to have a story sent out, and critiques have to be a certain length to count. It takes about four weeks for stories to make it off the 'queue,' and another incentive to critique more is that 10 or more critiques in one week can earn a skip to the front of the line in the next week's manuscripts. People can expect anywhere from 5-20 critiques, depending on the content, length, and genre of their submissions. If you only write novels, no problem: they have a special system for getting people to read critique novel-length works. Also, there are a lot of good resources for how to critique. Free to join.
On Writing by Stephen King - One of the most successful writers of our time. Whether you like his prose or not, you have to respect his ability to connect with a wide range of readers. In this book, Stephen King combines autobiography with very useful advice and thoughts on writing. From outlining, to improving, to taking time off between first and second drafts, there's something in here for everyone. Different things work for different people, and while King's process might not be right for everyone, it's interesting to see how one of the best does it.
The Elements of Style by Strunk and White - William Strunk Jr. was an English professor who wrote a little handbook on writing for his students. Years later, one of those students, E.B. White, rediscovered the manual and thought it would be a waste not to share with the world. The result: a pocket-sized guide on grammar, style, and overall effective writing. It answers many of the small annoying questions that plague the writing process, such as that versus which, and when to use a colon, semi-colon, or dash. Peruse its pages for commonly misused words and phrases, and read up on how to omit unneeded words. Definitely a must-read for any writer.
My Writing Spot (Update: Now defunct.) - Considering I've written and/or started a lot of my short stories on my phone using this app, I can't help but recommend it. It's a very barebones word processor for the mobile phone which can also be accessed online. When I'm on the go (on the train, standing in line, bored at work) and I have a sudden idea, I whip out my phone, jot down some scenes, and retrieve it from their website the next time I'm at a computer.
Self-Editing for Fiction Writers by Browne and King - Professional editors give it to you straight: big publishing houses are polishing their books less and less, and more and more agents won't look at a manuscript which doesn't have that professional sheen, even if it does have potential. This book doesn't urge you to go out and hire a professional editor, but gives you the tools needs to accomplish a lot of the clean-up work yourself. Some of the topics include: show and tell, characterization, point of view, dialogue, repetition, and voice. See your work from how a professional would see it to give yourself an edge. Easy reading with examples from classics we love. A must-have.
Those are things I use the most. What about you? Let's keep the list growing.