Take a picture of a teacup for the cover of the invitation. You can make color copies of it for each invitation. You are invited to see what the teacups can say. If you don't bake or don't have the time, go to the bakery. After all the party is about socializing, not preparing.
Fresh fruit is also good to have.
Finger sandwiches can be made with a fancy bread like pumpernickel or multi grain. Use any filling you like. Cut off the crusts and cut diagonal. Stack them on a few plates for display. The trick for the food is to serve things that are easy to eat while sitting on the sofa.