This may sound crazy but this is what I do, I put everything (the yarn, pattern, needles etc.) for the next project that I really want to do in a clear bag, put it by me as a sort of incentive to hurry up with the current project. Of course this only works if you are a finisher/only work on one project at a time. If that doesn't work, try committing to working on it 10 minutes per day. You will be surprised how much you can get done.