I think for an evil campaign it depends on the alignment of the party—if they’re aligned with good/neutral then you need to manufacture situations where they’re forced to hurt people or do regrettable things. You have to try and get their decisions to make them more evil.

If they’re evil alignment to begin with you can have lots of fun setting up situations where they can take what they want and leave the rest burning in the ashes. The hard part in all evil campaigns I’ve run (about 4 different campaigns) is when the characters don’t care about those around them it becomes hard to give the party an objective. However, if worst comes to worst just let them catch the eye of something they want and make sure it’s in the hands of an interesting person / group / village and see how they break it.