Our school doesn't even require us to pass the Family Med Shelf (only rotation where this is true), so I didn't really study for it... ended up with a "passing score" anyway. I looked for good resources, but I really don't think there are any. I think you just have to trust that your knowledge from the first two years of med school, other rotations, and your Family Medicine rotation will get you through it. I'm sure most people will be fine.