Ted Hughes said this quote

What I am going to propose is that you write a novel.As you know, the practical advantages of being able to write out your thoughts fluently are very great. For one thing, when you are used to writing them out, they present themselves, one after another. When you are not used to writing them out, they mill around among themselves usually and you see nothing but heads and tails of them when you sit down to get them on paper. I know from my own experience that the first two or three hours of every exam I ever took were spent simply getting my pen warmed up, and by then it was too late.