Hemingway talks about writing in A Moveable Feast
"I always worked until I had something done and I always stopped when I knew what was going to happen next. That way I could be sure of going on the next day. But sometimes when I was starting a new story and I could not get it going,...I would stand and look out over the roofs of Paris and think, 'Do not worry. You have always written before and you will write now. All you have to write is one true sentence. Write the truest sentence you know.' So finally I would write one true sentence and then go on from there.
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I learned not to think about anything I was writing from the time I stopped writing until I started again. That way my subconscious would be working on it...I would read so I would not think about my work...Going down the stairs when I had worked well was a wonderful feeling..."