I have a tried-and-true system to finishing first drafts. First, I create the shell: type out headings and subheadings, insert page numbers and create a table of contents, and pull together a fancy cover page. If this is all I do on the draft on any given day, at least I have something a few pages long to hang my hat on. After this first step, starting the substance of a first draft seems a bit easier. Today I finished drafting a petition for review to the Texas Supreme Court, which entails a scosh of stress and just a button's worth of pressure, to say the least. This first draft is most certainly a working one and will see a dozen pens' worth of red ink before it is all said and done. One of the best parts about finishing a first draft, regardless of what it is a draft, is having a tangible finished product at the end of the day. It may be an absolutely laughable finished product, but it is finished nonetheless. I'll give this one a few days before I enduring the cringe-inducing editing.
