This is only tangentially related to the above (which is why I've split it off into a reply).

Something I recently notice myself doing is overestimating my ability to finish tasks in a short time period. I believe this overestimate is a major factor in my procrastination: if I knew exactly how much difficulty I'd have doing something both quickly and well, I think I'd be more motivated to start earlier. As it stands, I have been able to perform very well under time constraints sometimes, so I tend to assume I'll be able to every time, and end up putting things off past the point where I'll be able to do them well.

Just noticing that I was doing this, and repeating to myself that my estimates of my own ability here are extremely suspect in that they seem to differ substantially from what historical evidence suggests, has gone a long way to improving my ability to get things done. This improvement is why I've been thinking more generally about the idea in the parent.