Another pro tip to add to those already here...

Wake up and write down what you can, ASAP. That's as soon as you regain consciousness, go straight to your DJ and write it all down. If you can't remember much, I find that as you write things down, more and more details start falling into place. I've started off writing small sentences and then remembering things like; "Oh yeah, whilst that happened, there was X person nearby who was doing Y thing" results in me writing up a paragraph or two.

Give it a go, you should be pleasantly surprised :3