I'm a big fan of brainstorming. There's nothing as free-flowing as writing the main idea in the middle of the page and branching out into sub-headings to help you connect better with your concept.
A couple times this week, I had vivid, scenic, emotional dreams that inspired me to start two new writing projects once I finish my current manuscript.
As soon as I woke up, I jotted down everything I could remember about my dreams in the notebook I keep beside my bed. Then I transcribed my notes into Word. I have a whiteboard in my office, and thought it would help me organize my thoughts a lot more if I had the same kind of thing as a computer software application.
So I did some research and came across Mindomo, a mind-mapping online application that lets you create mind maps on your computer. You can even publicize some of your work if you're collaborating with a writing partner.
While the premium plan costs six dollars a month, the basic version is free and pretty much does the only thing I want it to: draft simple mind-maps that will help me think of all angles, potential characters and storylines, and themes that correlate with the original idea written in the middle of the mind map.
Check out the application here and keep your brainstorming notes organized.