I always make the birthday child the star of the show by getting them to help me with my prized coloring book routine, in which they are made the magician, dressed as a magician, and givin a magical stage name. It is great for photos that the parents want to make and it is a memorable thing.
Also, there is a newspaper cut out there that is really simple to do...I think Gene Anderson wrote about it in his newspaper magic book. You roll up a newspaper and cut it once. Then when you unfold it, there is a large star cutout in the middle of the page.
I believe it was ken scott I saw use it and hold it in front of the birthday child as he said "Tada the star of our show!" then he gave the child the paper.
Speaking of actual star effects, I know in one of the Pack Small Play Big videos there is a terrific star trick; Starcle.