I noticed significant improvement at work in specifically listing how long I expected task to take, over creating a list of everything that needed doing. That said, the improvement was in how I felt about how much I got done: "today I did more than I thought I'd be able to in eight hours, awesome!" versus "gah, only got half the things on my list done today." which could both be reactions to getting the exact same work done.

Having realistic expectations of how much I will get done boosted my motivation.