The busier I get, one thing becomes abundantly clear: If something is on my "To do" list but no date or time has been set, it stays on there for a really long time.
I've started to institute a new policy and it has been helping me. Perhaps it will also be helpful to those of you out there who are feeling frustrated. Whenever I have committed to getting something done, I go to my calendar and schedule an exact date and time to do it. This helps me get things out of my inbox and limit the number of "To do" lists I have and it also helps me plan better. If I can see on my calendar that I have certain tasks to complete, I have a much more realistic picture of how my time will be spent abd how much time I actually have.
Some books that deal with this and are also very helpful include:
Take a second today to ask yourself if you are using your calendar in concert with your to do list. How much is sitting there waiting to get done and what's been scheduled?
If there's a lot sitting there, take the time to schedule a time to do it or get rid of it.
I feel a lot better when I do this, and I'm sure you will too.