I choose whichever task contributes to my most important life goal. For example, I’m about to finish up my Bachelors, so I generally choose schoolwork for my deep work session.
I look at the list and determine which tasks have the most urgent timeline. If they have a similar level of urgency I start with the task that is of lower interest to me as I find it easier to go from low interest to high interest tasks.
First of all I choose only those tasks that are important for the current professional activities, then I deal with projects that are meant for my final goals.