I took a songwriting course from a guy named Jai Josefs. He has written some books on the topic, that you might find useful.

The important thing (according to Jai) is that the verse and chorus have contrasting elements (similar to what anthrax said).

So if the verse has long notes, the chorus might have short staccato notes. Or, if the vocals are all starting on the downbeat in the verse, start on an off beat in the chorus.

If you start to analyze songs with this idea in mind, you will find a lot of ways to make a contrast between the two, even if the underlying chords stay the same during both verse and chorus.

Have fun, hope that helps.

Jon