Although the forms looked voluminous, they were made up of large blocks in which to print names and addresses with lots of white space in between. I chose to have a phone interview along with these reports rather than go into the Social Security Office. In my case, I had no medical records in my possession. Consider your symptoms carefully and thoroughly. I made a list of every symptom I have experienced - these might include fatigue, vertigo, headaches, pain, vision disturbances, memory loss, tingling etc.
Hard details are in and generalities are out.
These are some thoughts but brainstorm with someone about WHAT has changed in your abilities and stay with the facts. Stating that you can't do yard work anymore because of your MS does not help someone reviewing your case understand WHY you can't do yard work. Saying that your ability to wash your hair has changed won't help the person assigned to review your case. Be prolific and given a choice tell more than less and tell everything no matter how unimportant you may think it may be. Any change or difficulty is relevant and useful and helps the reviewer determine your status.