As others have mentioned, be sure to write bunch of headers of what you're actually going to write, then work from there. Start by giving each section a title,

As others have mentioned, be sure to write bunch of headers of what you're actually going to write, then work from there. Start by giving each section a title, then each sub section, then each paragraph. Below each title, give a one line summary of what you're going to write about in each part. From there, you're simply filling in the gaps. This method improved my productivity with writing 10-fold.