A good idea is like a dream. Perhaps it is a dream, in waking form. It comes misty and bright. Beautiful, floating in your mind. Catch it before it flies away because it will fade to a mostly forgotten memory in minutes. No matter how certain you are that you won’t forget it, I bet you will.
You don’t need to fully develop every concept as it flashes across your consciousness. But, if you think it is worth turning into any kind of authoring, write it down. Where you write it doesn’t matter, as long as you remember where. Your phone, a piece of paper, the white board in the kitchen, a couple of lines in a post on your dashboard. The important part, is to do it quickly. Put at least a sentence or two somewhere and try to make sure it is something which will help you remember what you saw.
Ideas, flashes and thoughts are ephemeral. Reality will steal them, so catch those ideas. Those ideas you are absolutely sure you couldn’t possibly forget will be gone before you turn around twice. Catch them before they get away!