The principle SEAL taught is what he calls the 40% rule — which essentially means people feel maxed-out mentally and physically, and thus stop, when they are at only 40% of their actual capacity. Going past this 40% capacity is when it becomes uncomfortable. Thus, SEAL’s mantra, “If it doesn’t suck, we don’t do it.”
A useful strategy is what I call the mode-switch. If you find your attention being pulled by something (exogenous attention), stop and check if it aligns with your goal at that time (thus, tapping your endogenous attention). If so, then exercise that endogenous, goal-directed attention to select and modulate the information.