Therapy Dog Testing

Hi,
I signed Cricket up to test her for her therapy dog certification. My training club has a real good group that does therapy dog visits on a regular basis and I feel Cricket would be a good therapy dog. She has a real stable temperament, loves people and is a very calm, patient dog. She already has her CGC and we are going for the TDI certification because that's what my club uses for their group.

I'm all of sudden really nervous though. We've been training a lot lately, I'm familiar with the test components but I'm afraid of being so nervous that day and blowing the test.

The one thing we are really struggling with right now is the leave it requirement. According to my friends, the tester is going to put down a bowl of cat food and the dog is required to leave the food and then walk past (or over?) the bowl of cat food. I've been told that I'm not going to be allowed to body block her which is what I would do in a real world situation and that the evaluator is going to be real picky about this component of the test. She's not allowed to go for the food and the leash can not get tight.

We have been working really hard on this, but cat food is Cricket's weakness and I'm having a hard time strengthening her "leave it".

I've been practicing with lower value items and building to higher value but I don't know that we are making any progress. Does anyone have any tips for building a solid leave it behavior in a few weeks?

Anyone else ever done the TDI test that can give me any helpful tips?