I have tricked myself into achieving ambitious goals by breaking down the next few days' objectives into small, doable tasks. I will even go as granular as 'make cup of tea and fix typo while kettle boils'. I've found that if I can get into an automatic mode where I'm constantly checking off tasks, repriotising and refining what is still to be done then success creeps up on me. At some point during most days I realise I have made significant progress; at some point during the project it occurs to me that I am done.