In my opinion there's no such thing as "over prepared" in terms of how prepared YOU are for the appointment. But
how you present yourself to a doctor makes a huge difference a lot of the time.
--If you might forget something, write notes to yourself on an index card....something small. If you start reading off a large sheet of paper, your doctor may start to roll their eyes and tune you out.
--Make everything you say as succinct as possible. Do not repeat yourself or go off on tangents or tell stories about how something is in your life. For instance, just say, "I have a very hard time doing the ordinary things one needs to do day-to-day, like laundry and house cleaning." Don't say, "Well, last week my family was visiting and I had to clean the house but I didn't have energy to get it as clean as I like, and my family is very critical, so......." and so on.
--Never argue with the doctor. It won't help, won't change their mind, and can go on your record in a negative way.
---Remember that these days because it is all computerized everything and anything that happens, is said, or is perceived by the doctor (whether perceived accurately or not) can go on your
permanent medical record, be seen by every single medical professional you see in the future, and will influence the kind of care you get. You get one doctor saying you are malingering or a hypochondriac and every doc you see from then on will be looking for signs of that.
--Look the doctor in the eyes. Be very polite. State everything in a "just the facts, Ma'am" manner.
Stay calm. Do not get emotional no matter what happens. That will be cause for a negative impression.
--If you fear you may not be able to advocate adequately for yourself or you might get emotional, take a supportive person with you, if you have such a person.
--Be very careful with anything you say that could be interpreted as being suicidal. Even if you feel as if your life is hardly worth living because of the pain you are in, it's risky to say so, because you can end up with "suicidal ideation" on your record, and that won't be helpful to you (and could even lead to a hold period in a mental ward if someone wants to take it that far).
---Go in with confidence. Tell the truth. You know what you know and you know what your body is doing. They don't. Just tell them and let them decide what they are going to do or not do. If you don't like the doctor, and can change doctors in your particular situation, then do so. But be careful about going from one doctor to another asking for medication, because that will eventually be seen as "drug seeking".
---Finally, remember that when talking to a doctor, unless it is someone you have known for years and know you can trust, you have to remember that you are talking to a person who has the potential for unreasonable power over your life....kind of like a police officer. Even when you know you are in the right and being 100% honest, you have to be careful what you say. Keep that in mind at all times, and behave accordingly.
What I have just written sounds as if you almost can't win, doesn't it? Well, many times that's the case. There ARE good doctors out there; ones who will listen to you, believe you, and do everything they can to help. And there are doctors who are arrogant and apparently don't even like people. It's hard to find the former, sometimes. But all you can do is keep trying, and do your best to present yourself in the best light possible each time.