the paperwork portion is overrated. you can have volumns and volumns of paperwork and pics and still be asked for more evedience. When my wife did had her interview, we gave them everything we had and they still asked for more. We sumitted the exact same package to them again and we got pink. it's important but not that important. Documents can be created by anyone. Phone logs/bills, chat sessions, emails can all be generated by anyone, therefore thay have little weight.
The CO's are not interviewers, your SO is not applying for a job. The CO's are interogaters. They want to find out if your relationship is genuine. your SO is already paranoid coming into the interview. They have heard horror stories from their friends and neighbors, what questions are they going to ask? They are afraid of getting something wrong. They have never had an interview in their lives. They don't know how to act, nor react.
That's why interview peparation ins the most part of the interview. if you can get her to relax and be confident, this will be a huge plus, better than any part of your paper package.
Another tip would be to have some green flags. We know all about red flags. sometimes things are beyond our control.
My green flags: have your family (parents/siblings) at your engagement/wedding. Why? Because no one is going to fly their family to VN for a fake ceremony. I would rather make one trip, with my parents being there, than make 5 trips by myself.
Another green flag: take pictures with her friends. Why? Because she is not going to introduce her real friends to her fake husband.
Good luck man.
What's next got a reaction from Hurry&Wait in Is there anything we can do now to prevent just in case out case get send back to USCIS?