Assuming you have completed the planning step of the writing process by using idea tags, idea maps, or idea lists, you are now ready to write a rough draft, the second step. I emphasize the word rough because quality is not yet important, as you'll revise, edit, and proofread in the third step, quality control. Three points matter during drafting, as you are seeking to maximize your writing time: speed, uniformity, and volume. Remembering the acronym SUV will be helpful as you plow through your rough draft.
Speed – You do not need to write at a breakneck pace. Steady is the operative word. When it comes to writing, steady is speedy. Just move your fingers to push that cursor forward, paying no attention to organization, sentence structure, grammar, spelling, or punctuation. Get it all down. Do not rewrite until you are through drafting.
Uniformity – You created a plan in step 1 to move easily through the first draft, so stick to it. It might not be a perfect pan, but it's what you've got.
Volume – I'm a big believer in less is more—but not in the first draft. More is more when drafting to give you a lay of the land when quality-controlling. Leave nothing in your plan behind.