Were you to move into authoring RPG material, where would you go to for advice? I am thinking of publishing a whole line of gaming products. However, I am not adverse to hearing more focused ideas.
I'd like to get at things I did not know but need to know.
Crapping on your Dream: Freelancing 101 by Robert Schwalb
Five elements of appeal in commercial RPG design by S. John Ross
Getting started by Monte Cook
Game Industry Etiquette (Or, "How to Avoid Looking Like a Pathetic Jerk") by Monte Cook
Finally, a useful piece of advice from Ed Healy:
"The best way to learn about game design & publishing? Design a game and publish it."
Read existing campaigns. This is by far the best thing you can do to get yourself in the mode of campaign writing. There are some really well written modules out there, both by game publishers and individuals. Read them. If you have time, run them for a group. You'll quickly get a feel for what's fun, what's tedious, and what good (or bad) organization looks like.
Immerse yourself in your campaign setting. I can't stress this one enough. Research the society, economy, politics, and geography of your game world. If you're creating a new world from scratch, write yourself a Wikipedia-style article about your world and the major details about it. Know why city/state/country X is allied with city/state/country Y and why it's at odds with city/state/country Z. Know the powers that be, whether it's kings or governments or corporations. If your campaign setting is an established one, pick up a novel or five set in that world (and read them).
Look at resources outside the RPG community. Writing tips and advice from other sources apply just as well to RPG's as they do to other things. You still need all the major components of a story to run a successful adventure.
Write the story before writing the campaign. I don't know if a lot of people do this, but it worked for me. Once I had a concept in mind, I sat down (every day for a few weeks) and wrote a short story about it. This forced me to have a grasp of where the story begins, where it's heading, and where it ends. Once that's done, it's relatively easy to adapt it to a campaign and design the roleplaying and combat encounters.
Where to go for advice? Here is fine ;> or any of various sites at which those who've actually done it can advise you.
imho the primary resource is one of Support for your immediate physical and mental environment. If you have that, you can research the pertinent game-specific details. Thus:
For your physical environment...
And on the mental front:
A good place used to be The Forge. This website raises strong emotions, but it's undoubtedly good for publishing guidance. It is slowly closing down, but it's still worth posting there as a first step.
The Forge has a particular idea of what makes a good game: for example, expect a hard time if you're publishing a fantasy game. Crucially, however, they will give you the information you need: writing, design feedback, how to choose a printer, how to employ an artist. Everything. They have an ethic of encouraging new publishers.
Try reading through the Forge archives on particular topics. For example, if you want to do a print run, you'll get some good advice (most importantly, don't print 10000 copies).
Most of the Forge community have moved on to Story Games. That may be worth a try, too.
Generally, if you can speak to the indie games crowd, you'll probably find someone to point in the right direction. Follow them on Twitter. Email them politely. Speak to them at conventions. There are people around who will advise you, but they don't gather in one place any more.
(I hesitate to give you names! But think of the well-known indie games and try poking around. If you have a favourite game, contact the author politely. You'll find someone.)
Finally, you could ask more specific questions here. I recently published a book, Stealing Cthulhu, which sold very well in preorders. I'm happy to answer questions and I imagine other would be too.
Mongoose produced a book called 'I Am Mongoose And So Can You' a couple of years ago or so on getting into the industry, you can pick it up on DriveThru. It's quite highly rated and looks to be reasonably comprehensive.
Probably the single most important rule in Game Publishing:
Playtesting is not optional.
And remember: you running your stuff for your friends isn't really playtesting; it's development, perhaps, but not playtesting. Playtesting requires people who aren't you to run the game/supplement, and tell you what they didn't understand, what didn't work, and what didn't get used.
Listen to your playtesters. You don't need to implement their solutions, but you do need to cure any common deficiencies.
Editing isn't optional, either
If you can't do it, find someone who can. With the massive glut of material now available, anything which makes a difference is important, and the first complaint I see in most reviews of most small press stuff is the "crappy editing."
Hell, use your playtesters for editor's review, as well as playtest. They get a "reward" of a nearly complete copy, and you get lots of sets of eyes looking at it looking for typos.
