What is something you know a lot about? Make a mind-map about that one thing.
What is something you know a little bit about? Make a mind-map. This time you will need to "extend your thinking" by including words or thoughts that are somewhat connected.
What is something you know very little about? Make a mind-map....and let your thinking wander. Add ideas that could be connected, or some how related.
A "freestyle" brainstorm is a type of thinking where you get to choose your direction. Connections are made between ideas, although they might not always be connected to the main topic.