Yes like you I was too much anxious to write but always procastinate in it . One reason honestly i did not know from where to start this journey . How to proceed is another question .
Including this post i will describe all of the tips which helped me and Insh Allah will help you as well .
One way to cross this chasm is to write often , people often start blog for traffic purpose but one important tips to overcome the fear of turning ideas into words is to write blogs. Start blog on any good topic and just start emptying your thoughts in it.