Writers: do you improvise as you write, or do you plan everything out before you start writing?

Writers: do you improvise as you write, or do you plan everything out before you start writing?
When I was younger I had the ability to make up stories as I went along. I’d write a beginning, usually a random scene that just sounded cool, then continued writing from there having no idea how the story was going to turn out until I got to the end. Now I’m experiencing trouble with that. I get writer’s block if I try writing without planning things out first. What do YOU do when you write? Do you make up your story as you go along, or do you plan everything out first? And if you plan, could you describe a little bit about what types of things you plan for?

“Those who fail to plan, fail to finish.”–Anonymous

I outline my story before I write it. The outline isn’t a figurative Bible for the story–I let myself stray from it if I get a good idea–but it does guide me from the beginning to the end. I use the essay-outline method and I also make profiles for my characters. I can always rewrite part of an outline if one event sounds better than another. I can always make more character profiles. However, it’s almost impossible to start planning in the middle of a project, when you’ve hit a dead end.

I get pretty obsessive when I plan. This is the stuff I plan for:

1. World-building. I design a world. It takes a long time–my last one took six months. But you build a world once, and you can use it many times. It essentially pays for itself.

2. Outlining. I outline the story, as I said, using the essay-outline format. It consists of main events that happen and some rough details that support the main event. When I write the actual story, I fill in the blanks I left in the outline.

3. Character-profiling. I profile a character’s physical, emotional, mental, and social characteristics. If, while outlining, I get a new character, I profile for him/her. If it’s a minor character who will do something big, then disappear, I usually only profile for physical and mental characteristics.

I’ve never been able to finish a long story without an outline.