I've found that I'm much more likely to complete and succeed at a given task by creating very specific goals for myself, and breaking down my goals into specific tasks. It's the same concept that I do in building software writing out stories for each feature, etc, but applied to myself.

For example, I have a specific goal to read 3 chapters in Godel, Escher, Bach every month until I finish the book. I'm also challenging myself in other areas of my life, like eating, running and biking, etc.

Most importantly, though, is that my goals are all very short-term: most of my goals are in 1 month chunks, but some are in 1 week chunks. Only very few are more, and they usually are broken up into sub-goals with 1 month chunks or less.

At my work, we like to create goals and tasks that are SMART: Specific, Measurable, Attainable, Realistic, Timely.

There's no way you'll finish something if you don't know how to get to the end, how long it will take you, how much effort it will require, and how it will look when you get there.