Create a strict schedule for each of the seven days. The best way to keep from becoming discouraged or distracted is to plan ahead before you sit down. As author John Coyne explains, "You'll need clearly defined patterns to keep yourself working." Once you set your schedule, do not vary from it.
Have your story outline ready. Outline plot, characters, action, emotions, and any other important aspects of your book. Do not rely on your memory or imagination to keep the flow of your novel straight.
Set aside a dedicated place for writing. Stephen King says it's best to write in a place free from distractions, in a room or space that is private and meant only for writing. This means no telephone, no interruptions, no Internet and no TV or anything else but you, your novel and time to get it done in peace.
Seek help. Telling your friends and family about your goal will get you motivated. Don't be shy about enlisting their assistance. They can bring you coffee, rub your shoulders, or let you know when you really need to take a break. There are also online writing groups where you can interact with other writers for feedback and encouragement to get you through the tough times.