I went in with all my medical records and conditions highlighted for each issue. The Dr. actually asked if she could review them since she preferred that over scrolling through the computer. She actually stated that she wished more patients would do that. Also, she was glad that I was in jogging pants and a T-shirt. She wished more patients would wear those type of clothes especially for range of motion tests, etc. She was very nice, understanding and detailed. My last exam was just yesterday and I don't know the results, but at least she verbally stated that all my information we disussed was verified in my records and matched my symptoms, etc. So, credibility was there.
Now, not all Dr.'s want to see your medical records that you brought in. But, I also created a list of dates for each of my issues I was claiming. This helps alot since they want to know when each issue started, when tests were performed, surgery dates, etc. I went through my entire records and made lists for each event, even Physical Therapy sessions, steroid injections, medications list, etc.
During the exam, be honest, say what causes things to hurt, don't try to over succeed on ROM tests, stop when it hurts or is uncomfortable. State a pain level (1-10) and know # times a year things flare up. Having a documented approach will make the appointement easy since the medical documentation should support your current symptoms. Also, some appoointments go quick, some take longer. Don't let that affect your impression since the RO may only be asking for 1 simple piece of information. Still, you can ask the Dr. about your concerns, why an issue wasn't evaluated, etc. Communicate.
Results from the C&P are usually posted 3 days after the exam on My HealtheVet, so sign up for that account if you haven't already.
Finally, be polite and courteous. The examiners are there to document what they see and to match it to your records. There may be some bad ones, but all of mine have been good and were female except the Dental Dr who was male. I believe showing respect from the beginning doesn't hurt. However, attitudes can definelty hurt the situation. Be calm, polite and honest and all should go well.
Good luck!