We can't avoid the ups and downs in life, but we can develop stamina for navigating them.
Much of what interferes with maintaining inner peace is our tendency to think too much about the past, or worry too much about the future.
The most reliable recipe for emotional exhaustion would be losing energy to past things we can't change, or future things we can't control.
We reflect on the past through the hard-won wisdom we gained surviving it. Then, we tend to beat ourselves up for not using that wisdom to avoid the same failures and pain that helped us earn it in the first place.
When it comes to the future, we fail to trust ourselves. We imagine worst-case scenarios with catastrophic outcomes. This tendency is supposed to prepare us, but it only consumes us with anxiety and self-doubt. I have yet to meet someone who can sufficiently worry themselves to the point of total confidence!
The best way to boost emotional resilience is to conserve your energy for the things that really matter, rather than wearing yourself out with worry or regret. Take your lessons from the past, and then leave it there.
When it comes to the future, trust yourself to manage it. I like to think about a bird perching on a branch--it's not worried about all the possible ways the branch might break, because it trusts its own wings.