I've learned that I get blocked when my subconscious mind is telling me that I've taken the work in a wrong direction, and that once I start listening to what my subconscious is trying to tell me, I can work out the problem and get moving again.
I found college useful for a lot of other reasons. It exposed me to a great many influences I wouldn't otherwise have encountered, and gave me a lot of time with some very intelligent people whose thoughts are still with me.
Even if you only want to write science fiction, you should also read mysteries, poetry, mainstream literature, history, biography, philosophy, and science.
That's why editors and publishers will never be obsolete: a reader wants someone with taste and authority to point them in the direction of the good stuff, and to keep the awful stuff away from their door.
The Internet offers an interesting combination of advertising and community by participating in the community you can become an advertisement for yourself.
Working within the limitations of the shared world generally made the writing easier, because I didn't have to invent any of the characters or background, which is usually the hardest part.
I can't speak for the other authors, but what I hoped to achieve was to illuminate certain corners of the Lucas universe that hadn't yet been explored.
It's hard to generalize, because they're all different. When I started, I decided to take as much advantage as I could of the freedom offered by the SF field.
Some of my ideas were shot down by Lucasfilm because they stepped on territory that has been reserved for the movies. I didn't have a problem with that.