As #harshwritingadvice trends on Twitter, here's a recommendation from DBC Pierre: "Leap before you look."
With his 2003 Booker Prize-winning debut Vernon God Little (reviewed here), the author decided just to "get all the words down, see how they tasted and adjust them". The task then was to "get over the gibberish and look", finding a way to edit, develop and shape those words into something that worked. When he did so, he discovered that "the seeds were already there in the blur of the pages, so I dug them up, extracting each one into a document of its own to expand in isolation". In that way, he treated the emerging novel like "a contraption that could be polished piece by piece".
It's sound advice for those who feel compelled to write in a strictly linear fashion and agonise over the finer detail of each and every sentence before moving onto the next - myself included.