Well I did a lot of experimenting with throwing things both at sims in my family performing (the success rate was about 95%) of the time and throwing it to my daughters account which about 5% of the things thrown would go through. Mainly flowers and even got the cow plant thru
But if you want to cheat on getting perfect vegetables and fruit that is the way to go if oyu have a performer in your household
Another tip, if you go to the show and cheer all the time for your sim (ei. dance around or wave hands in the air) you will almost always have a great show, even if your sim is just starting out and it is a good way to win the Sim Fest also.