Applying for residency-I'm nervous.

We finally got appointments at the San Diego consulate to apply for permanent residency. We have the forms and we're gathering up all the required documents.

Please, any of you who have been through the process, can you share your experience?
What is it like? Is it a grilled under a bright light kind of interview? What kind of questions will I be asked? I know it is ultimately up to that particular officer, so I definitely want to get on their good side. Any hints, tips or tricks are very much appreciated.