When you reach the editing stage, it is often the case that you can get too involved with the story to detect errors. You can see words in your head that aren't actually there on the page, sentences blur together and errors escape you, and you follow plot threads and see only the images in your skull.
When I get started each day, I read through and correct the previous day's 2,000 words, then start on the next. As I reach that figure, I try to simply stop and not go on until reaching a natural break. If you just stop while you know what you're going to write next, it's easier to get going again the next day.
When I started out, I didn't have any writing routine, I had a job. Writing was a hobby I indulged in over the weekends or in the evening when I wasn't too knackered, watching TV, reading a book, or up the pub. I only ever started counting words upon discovering, in John Braine's 'Writing a Novel,' that this might be a professional approach.
With fantasy, one often has to think of a well-loved series before narrowing the selection to a favourite book. So it is with Zelazny. I've read his 'Princes in Amber' books so often, I know them almost verbatim, so much so that I am now trying to forget them so I can return to them with renewed pleasure.