I bet you've heard about Tony Buzan's idea of mind mapping. It's my favourite way of learning, planning, revising and organizing. Mind maps help me develop my creativity, although my drawings are very simple. Of course you can use a bunch of online tools and software, but I prefer pen and paper (or colourful pens and paper).
How to make a mind map? Here's a mind map about mind mapping:
And here's another mind map I've made. I'm very proud of it.