Step 1. Analize what's the possible consequence / event that you find undesirable
Step 2. Determine whether there's something you can do to prevent it: if there is, go to step 3, if there's not go to step 4
Step 3. Do it, do that thing that you believe can prevent it. And after you've done it, go back to step 2 and reevaluate if there's something else.
Step 4. Since there's nothing else you can do to prevent it, accept the fact that this consequence might happen and adapt to it... you already did all you could do given the circumstances and your current state/ability, you can't do anything about it anymore, so why worry? just accept it. Try and make it less "undesirable".
Step 5. Wait. Entertain yourself some other way.. you did your part.
Step 6. Either the event doesn't happen, or it happens but you already prepared to accept the consequences.
Step 7. Analyze what (not) happened and how it happened (or didn't). Try to understand it better so in the future you can better predict / adapt under similar circumstances, and go back to step 1.