To try yoga or meditation Apps such as headspace can help calm nerves and stress Keeping track of things that cause you to stress then finding ways of getting rid of them or easing them
The best strategy for managing stress would be to follow James 1:2 in the bible and count it all joy.
Explanation:
If you count it all joy then you simply can't get stressed about anything in life. You know everything happens for a reason and if you truly believe and trust that everything will be okay then you won't stress. There will be no reason for worry.
No, only doing crunches will not help. You will have to do a variety of excercises to help lose weight around the belly. A good example of excercises that will help you lose weight would be cardio excercises.