Waiting for inspiration is no way to write. One has to have a routine. Granted, that routine is likely to be a messy one. Take Lionel Shriver’s glimpse into her daily writing schedule:

Start with large, strong coffee. Read paper, doesn’t much matter which one. Concentrate on little stories. Dostoevsky snatched scads of ideas from newspapers. Self could not make this stuff up, so why bother?

…DO NOT LOOK AT EARLIER CHAPTERS. Do not pour through thousands of words searching for whatever Self called some character’s yappy dog several chapters back. First drafts rely on MOMENTUM. Refining adjectives does not count as work. Solving what-does-she-say-next and why-would-he-do-that, or making daily effort to construct at least one paragraph justifying stupid book’s existence – one paragraph other people might conceivably want to read in sloshing sea of unnecessary, look-at-me prose in which whole world is drowning – this is work.

There are writers who do not feel comfortable unless their prose has been raked over a dozen times until it is clean and sparkling bright. That can be done at one’s leisure, but as Shriver notes, momentum is all. If you don’t maintain a steady pace (helped along by routine) then you will not have anything to review later.