Get Superstar goals before unlocking new shops. If you just get by with your goal on the unlock levels and decide to proceed, do not go back after opening the new shop and replay the level later. Doing so will erase anything you did to the unlocked shop.
On levels where there are chefs or vampires, don't serve hippies until after the other customers have been taken care of. Serve all of the customers as fast as you can, except the vampires, chefs and hippies. The vampire and chefs will turn the hippies into either a vampire or a hot dog, then they will place an actual order--resulting in far more money than the typical $5 to $7. Also, when they say a hippie will take anything, they mean it. To clear them fast, just give them the next thing in your hand even if it is just sauce. In the flower shop, give them an unwrapped flower so that you have more time to make bouquets for display (buy the refrigerator case quickly). In the cake shop give them undecorated cakes. If you do not have the refrigerator cases in the flower shop and bakery give them whatever remains so that the points are not deducted at the end.