I was listening to a preacher this Sunday who was an expert at the bad news. His sermon was 90% bad news. Then when it was time for the celebration there was barely any energy or time to celebrate the good news.
I often talk about the preacher leaving physical energy to end the sermon strongly, but preachers must also ensure that the good news in the sermon outweighs the bad news. You may demonstrate the good news emerging among the bad news if that is your theology. If your theology is one of overabundance then demonstrate how where sin abounded, grace much more abounds. If your theology is one of liberation, demonstrate the good news of battling with the forces of darkness.
Whatever your theology, find a way to demonstrate that the Good News is better and more powerful than the Bad news. If you do not do this, your celebration will falter and your people will leave having heard and experienced more problems than solutions.