"John Brown and Sally Smith would like you to help them celebrate their marriage" then don't forget the basic information about the wedding:
Barring a themed wedding, chances are there is something unique about it, perhaps your wedding color. You can bring the colors of your wedding party into your invitations, although you do not want to just send out white and teal green invitations. Choose an interesting designed or textured paper in teal green and off set it with a sheer cover in cream. The best thing to do when using wedding colors for your invitations is to step out of the box and use your imagination.