allow God to redefine 'good' in your life
Let's apply another Scripture verse to our discussion.
"And I am sure of this, that he who began a good work in you will bring it to completion"
This verse points out another difficulty in applying this concept to our lives: the timing. The bringing to completion of good works in us takes time, maybe a lifetime. So Peter, who grieves the death of his friend, might understand that it will work out in the end, but struggles because that might not happen for some time.
So in that period of waiting, Peter must continue to love God (see part ii), and expect his love to overcome Peter's loss. It's that simple, but we don't make it that simple most of the time. So often an event like this will shake our faith; we think that since things aren't going so well that God is not looking after us, God is not good, maybe God doesn't even exist. I know that's how I feel.
But God cares more about our character than our comfort. God does not promise that bad things won't happen, instead he says when they do, "Fear not!" He wants us to press further into him in our weakness, in our doubt, in our fear. Because when we do, will will always find that he is working to bring it to completion in a great way.