Study.
It depends what specialty you go into. If you are in anything like family, internal, EM, etc. then you can probably pass it without any studying by the end of intern year. Most of step 3 is basic clinical knowledge you need to know to do your job correctly. Yes there are a lot of weird subspecialty questions on it....but you don't have to get all of those right to pass it.
If you are a pathology resident you better spend some quality time studying.
