Time boxing is also very helpful to me. Very useful tool. It helps me to focus and not to get overwhelmed with the complexity of the task or disturbed by other items on my to-do list. To work on something for 15 or 30 minutes is achievable even for tasks I feel resistance to. And often, after this 15-30 minutes, it is much easier to continue working on it.
The timer isn't a deadline. It just notifies you of when the 20 minutes is up. I don't even look at the timer when I'm working.
Personally, I think I need some sense of urgency to perform deliberate, spaced practice reliably due to a strong history of what may be something like ego depletion (not really well supported). Pomodoro has worked better for me than most methods as long as I have sufficiently well crafted goals because it forces breaks as well as time boxing for results when I have a tendency to overengineer (along the same lines as SMART requirements). Like exercise, if you feel really comfortable, there's a strong possibility that you are not making the desired progress. In such cases, those that are motivated positively by the stressors are predisposed to improve over those that do not get motivated in such a manner even if that would be the most optimal technique globally.
If it stresses you out instead, then yeah, find another method. But I found it to be really effective.
1) Just do the task yourself every time
2) Build a system to do the task every time
3) Get an open source system and learn how to configure it and hope it does everything
In the end, #3 wins if you can afford to hire people who know the system.
Not saying it's preferable to #3, but it's better than nothing. SAP and Oracle still pull in a combined $57 billion annually, for things like accounting systems...
Outside of email, I often get carried away with setting up a system for doing work instead of actually doing work. If I know I have a lot to do, I'll spend time thinking about how I might organize it in a list and track my progress. Sometimes I even open the App Store and look through more to-do apps!
Something I've settled on now is making a list (usually in an app called Clear), then going through it once a day and putting it on my calendar.
Putting things on my calendar has helped a lot. I think, "this is the time I've set aside to get this thing done. I'm not going to focus on anything else but this for the next 30min/1hr". It also makes me feel less guilty about relaxing when I've got nothing scheduled.