Study plan for 2nd year med student

Hi there. I am second year medical student from Turkey. As many of us who are on this forum I also want to do residency in USA.... i have some questions, but before i should explain situation in Turkish med schools:

through first three years here in turkey we are taught subjects in committee or block form. Many basic science teaches are science faculty graduates(PhD holders who are not medical faculty graduates), so many of our exam questions are detail based and not clinically orientated. Coz many students are crammers and we have available pass years exam question we cram about 20 days before an exam and as a result you pass exam with a score of 70 or higher. So simple 2 or 3 weeks after exam all knowledge you gain is lost and gone :)))

So my question is how and when should i start preparation for step 1?

thanks for your attention.