I went to DragonCon (a local fantasy convention) and took some courses from Michael Stackpole and Aaron Allston. They were great.
The best writing course I ever took, however, the one that literally changed my life is online, and called “How to Think Sideways”.
It’s given by a fantasy/PNR author Holly Lisle, but anyone can take it. Here is her website: http://hollylisle.com/
You will find A LOT of free How-to writing articles, which is where I first started to learn the craft of writing. How to Create a Scene, How to sharpen Conflict, etc. There’s a lot of them, and they are free so it gives you a good idea of her teaching style.
Then you have the writing course. http://howtothinksideways.com/members/
The reason why I love this course so much is it’s not just teaching you one writer’s style and methods. She shows you how to get results, every time, and tailor it to your specific writing needs. It’s not just a course in writing one book, but on your entire writing career. There’s a money back guarantee, and she takes money out of your account on a monthly basis, so it was a lot easier for me to pay for the course.
She also has a course on revision that saved my bacon, but you probably want to start with HTTS.
If anyone is interested and has questions for me, I am more than happy to answer them. 😀