One tool I use a lot is the Pomodone app for the pomodoro technique. You can use it on your desktop, or your phone – it’s a cloud-based application.
What sets the free version of Pomodone (I haven’t tried the paid version, so not sure what extra bells and whistles this brings) apart from other Pomodoro apps that I have tried in the past, is that you can synchronize Pomodone with other planning and list-making apps.
Practically, this means that I sync Pomodone with my Google Calendar and Todoist, and so click on a task to start logging pomodoros on this task.
Try it, and let me know what you think!