One of the biggest mistakes I made was jumping to USMLE World (UW) from the beginning of my study plan. USMLE World is a learning tool designed for people who already have a foundation of the concept being tested. You can learn a lot from that question bank but unfortunately there will be gaps of information which UW will not provide. It's better to get another source to get an idea of what you will be tested on.
For example, if you were to learn about electrolytes, UW will test you on it. However, you may not be able to understand fully on why certain things happen. So before you start make sure you start off that explains the basic. Also, if you just recently passed your USMLE Step 1, then you have a head start on your studying.