Below is a list of resources I have found useful in the course of my career as a game developer. Bear in mind that I'm not a programmer, artist, or musician, so this list doesn't include any resources to help with those crafts. Most things here concentrate on design or development generally.
The No Twinkie Database!
This page simply consolidates all the Twinkie Denial Conditions mentioned in my Bad Game Designer, No Twinkie! columns into one place. If you want to avoid egregious design errors, here's a place to start. On this page you can find them quickly, instead of having to read through all the columns to learn about them.
Journals and Magazines
The industry is just starting to establish properly peer-reviewed journals. There are a few professional magazines, but not very many. There is a huge number of gamer's magazines, of course, but I find that few of them are useful to me as a designer. They let me keep up with industry news, of course, but they seldom provide real food for thought. For design inspiration I read an odd mix of consumer
There are a number of professional events for game developers every year – some essential, some optional. Unfortunately, most are fairly expensive, which can be hard on a newcomer's wallet.
Developers aren't a very social bunch, but to accomplish certain
things you have to get together in groups. This page lists organizations dedicated to various aspects of the industry.
Books (for books I have written, go here)
These are the books that I consider important parts of my professional library (although several of them were actually discovered and bought by
my wife). The collection is quite eclectic, reflecting my varied interests, and many of them have nothing whatsoever to do with game development. They're works that I look to for background information and inspiration when designing a game.