To remind me when I need to Get Things Done:
Anything with more than one task is a project. Clearly understand the current, and the next task. Figuring out the next task is different from doing the current one.
Do not do both at the same time. Let the next task appear if it wants to, write it down, and forget it until the current is done.
Do pomodoros. Check at the end of each whether all of the above is still true.