If you're not getting around to things on your to do list, they are simply not enough of a priority. In the same breath, if you keep doing things at the last minute, they are simply not enough of a priority. Either you have too much on your plate, or you're in the wrong line of work.

Things should be a definite yes when you agree to do them. The motivation to do the thing in the first place should be enough to at least get it started on time.

No lastminute-itis.