Do the sample test that they provide to get the format, other than that you probably just need to set your alarm clock. If you're like me, and you'll be anxious if you don't do anything, then just do whatever questions you can get for free and review the really major primary care things like 1st line antihypertensives and ages for cancer screening. There is no other specialty more well-prepared for Step 3 than EM, which isn't bragging, because that's not particularly impressive - it's just the truth.