So it only makes sense to write everything down and then cut it if you have to. Don't save this for last or it will probably get lost. I have trouble beginning my papers. I never know how to start. Although a reader will be obliged to read the paper from start to finish, you can feel free to piece it together any way you can.
Many writers suggest beginning in the middle with the thesis statement and body paragraphs.
After all, it will probably be easier to write an introductory paragraph once you know exactly what it is that you are going to introduce. I have trouble finding the right words when I draft. I don't like the way my sentences sound. Just keep the momentum going while you write. I can't start drafting until I have enough time to finish the whole thing.