Don't Overstate or Minimize the Accident
Incorrectly describing the accident is no good. First, your incorrect description of the accident will be in the records and it will be used against you by defense counsel later on in the case. Second, your incorrect description may also be used to suggest your doctor didn't really understand the nature of the accident and thus can't be relied on to know what injuries were connected to the accident. Be factual and complete in describing the accident
Don't Overstate or Understate Your Symptoms
Don't understate or overstate your symptoms. If you understate, obviously, those statements will be used against you later. If for example, your broken leg really hurts and so does your back, but not as much as your leg, you should report both. If after your leg heals you've still got a back problem and you didn't report the back pain initially, the defense will use that omission to suggest that the back problem developed sometime after the accident. Overstatement can be just as damaging. If you report to your doctor that you can't stand for more than ten minutes or walk for more than five and witnesses or surveillance tape shows otherwise, you will have ruined both your credibility and your doctor's, who is relying on you to give reliable information.
Don't Hide Your Medical History
If you have a history of prior accidents or injuries, make sure you tell your doctor. It's important for your doctor to know and, if you omit this info, the defense will make it seem that you were intentionally hiding the information from your doctor as part of an effort to build your case.