This is a fantastic article by Rachel Aaron, author of The Legend of Eli Moonpress, on how to identify your best writing practices, optimise productivity, and drastically increase wordcount. 10K words a day is rather drastic and probably unfeasible for most writers, but regardless, any increase in output and quality will probably be appreciated by everyone. I also think that with a little bit of adjustment, these practices can apply to any creative freelancer–from artists and illustrator to webdesigners.
As for me, I’m a consummate panster, so I imagine this might be tough. (My making things up on the fly apparently flies in the face of whatever “efficient” image I project, but I have always been an intuitive writer.) I do, however, plan scenes before I write them–I just can’t think more than one or two scenes ahead.