Don’t write a detailed outline. Instead, write a list of short sentences. Scott Berkun calls these ‘sentence grenades, phrases loaded with opinions that generate shrapnel in your mind.’
When you read back your notes, you can expect ideas to explode in your mind. How these explode is entirely up to you – there is no right or wrong. You can abandon ideas or change the order or work with the opposite opinions. The only point is to withhold judgement on your writing until there are enough words on the page to work with.