I recently came across a system called the Pomodoro Technique. It is a time management technique developed by Francesco Cirillo in the late 1980s. It is named after a kitchen timer called a "pomodoro" and the idea is pretty simple. You set a timer for 25 minutes of work, then take a five minute break, then set the timer again. Every 4 sessions you take a longer break for 15 to 30 minutes. No matter how bad your task is, there are very few things we can’t do for 25 minutes.
The method is based on the idea that frequent breaks can improve mental agility and as work sessions are accomplished, you feel more in control and you can see tangible progress. The more in control you feel, the less stressed you feel and the quality of the work may even improve.
If you accurately record what you get done in 25 minutes that will help future planning and show up those hidden items that can take a bit longer than we expect.
I've seen this used in software development where two programmers work together on a screen review. That is a pretty open ended task but the defined sessions focuses the minds and charts progress. This also works with the idea that to solve any problem, you start by reducing it to achievable individual tasks and get each one done one by one.
Try it out and see if it works for you, at the very least you will get regular breaks and have a more accurate record of your efforts.