3 ideas
Divide everything into what is fully within your power (your judgments, choices, and actions) and what is not (outcomes, others' behavior, reputation, the body). Invest emotional energy only in the first category and treat the second as raw material to respond to, which removes the source of most distress because you stop demanding that uncontrollable things go your way.
External events carry no inherent good or bad value; the disturbance comes from the judgment we attach to them, not the event itself. Because the judgment is the controllable link in the chain, you can intercept distress by examining and revising your interpretation rather than trying to change the event.
Deliberately imagine losing what you value or facing the worst-case scenario before it happens, which both prepares you to handle setbacks calmly and renews appreciation for things you take for granted. Mentally rehearsing loss converts unexpected blows into anticipated ones and counters hedonic adaptation.