Named after the tomato-shaped timer that was on Francesco Cirillo's desk, the principle of time-management and productivity he developed is all about focus. It's about setting a timer(or keeping an eye on the clock) and setting aside 25 minutes of concentration on a particular project. Writing, research, thinking, planning, data entry or management-- all those tasks that we say we must do to be feel accomplished and productive. Meetings are not in this category.
They key to a successful Pomodoro is eliminating distractions and not letting yourself do all those silly little diversions that often take us away from your task to wonder where the time goes. There may be ideas that come up related to another project, or other, unrelated things you realize need to be done. Write them down on the notebook to capture them, but stay on your "tomato time" task at hand.
Then, you get 5 minutes. Stretch, engage in a little diversion, have a quick trot around the office and then return to a new task. Some folks need 50 minutes to jam along on a task, then take a 10-minute break. No problem. For a person that counts minutes and actions, this is a very valuable technique.
Try it out and see what you think. Here's a 37 second video with a demo if you need a visualization.