An open question is worth a thousand words
The first, and most important thing to master is the general history. Taking a good history is pretty much the basis of medicine. Forget CT scans, forget operations, forget penicillin - without being able to take a good history, you might as well be a plumber trying to build a bridge.
Learn this off by heart, and you will be able to manage everything; even if you don't know how to do a specialised inherited muscle wasting disorders history, you can do the standard one, and you will still get 90% of the information.